WORST_CASE(?,O(n^2))

Solution:
---------

  "append" :: ["c"(3, 3) x "c"(0, 0)] -(2)-> "c"(0, 0)
  "append#1" :: ["c"(3, 3) x "c"(0, 0)] -(1)-> "c"(0, 0)
  "cons" :: ["a"(0, 0) x "c"(3, 3)] -(3)-> "c"(3, 3)
  "cons" :: ["a"(0, 0) x "c"(0, 0)] -(0)-> "c"(0, 0)
  "leaf" :: [] -(0)-> "a"(0, 15)
  "nil" :: [] -(0)-> "c"(3, 3)
  "nil" :: [] -(0)-> "c"(8, 8)
  "node" :: ["b"(0, 15) x "a"(15, 15) x "a"(15, 15)] -(15)-> "a"(0, 15)
  "node" :: ["b"(0, 0) x "a"(0, 0) x "a"(0, 0)] -(0)-> "a"(0, 0)
  "subtrees" :: ["a"(1, 15)] -(3)-> "c"(2, 1)
  "subtrees#1" :: ["a"(0, 15)] -(1)-> "c"(2, 1)
  "subtrees#2" :: ["c"(3, 4) x "a"(0, 0) x "a"(11, 15) x "b"(0, 8)] -(8)-> "c"(0, 0)
  "subtrees#3" :: ["c"(1, 1) x "c"(3, 3) x "a"(0, 0) x "a"(0, 0) x "b"(0, 0)] -(3)-> "c"(0, 0)


Cost Free Signatures:
---------------------

  "append" :: ["c"_cf(0, 0) x "c"_cf(0, 0)] -(0)-> "c"_cf(0, 0)
  "append" :: ["c"_cf(1, 1) x "c"_cf(1, 1)] -(0)-> "c"_cf(1, 1)
  "append" :: ["c"_cf(4, 4) x "c"_cf(4, 4)] -(2)-> "c"_cf(4, 4)
  "append#1" :: ["c"_cf(0, 0) x "c"_cf(0, 0)] -(0)-> "c"_cf(0, 0)
  "append#1" :: ["c"_cf(1, 1) x "c"_cf(1, 1)] -(0)-> "c"_cf(1, 1)
  "append#1" :: ["c"_cf(4, 4) x "c"_cf(4, 4)] -(2)-> "c"_cf(4, 4)
  "cons" :: ["a"_cf(0, 0) x "c"_cf(0, 0)] -(0)-> "c"_cf(0, 0)
  "cons" :: ["a"_cf(0, 0) x "c"_cf(1, 1)] -(4)-> "c"_cf(4, 1)
  "cons" :: ["a"_cf(0, 0) x "c"_cf(1, 1)] -(1)-> "c"_cf(1, 1)
  "cons" :: ["a"_cf(0, 0) x "c"_cf(4, 4)] -(8)-> "c"_cf(8, 4)
  "cons" :: ["a"_cf(0, 0) x "c"_cf(4, 4)] -(4)-> "c"_cf(4, 4)
  "cons" :: ["a"_cf(0, 0) x "c"_cf(0, 0)] -(1)-> "c"_cf(1, 0)
  "leaf" :: [] -(0)-> "a"_cf(4, 0)
  "leaf" :: [] -(0)-> "a"_cf(14, 0)
  "leaf" :: [] -(0)-> "a"_cf(9, 0)
  "leaf" :: [] -(0)-> "a"_cf(1, 0)
  "nil" :: [] -(0)-> "c"_cf(0, 0)
  "nil" :: [] -(0)-> "c"_cf(1, 1)
  "nil" :: [] -(0)-> "c"_cf(4, 8)
  "nil" :: [] -(0)-> "c"_cf(8, 14)
  "nil" :: [] -(0)-> "c"_cf(4, 4)
  "nil" :: [] -(0)-> "c"_cf(4, 12)
  "nil" :: [] -(0)-> "c"_cf(11, 8)
  "node" :: ["b"_cf(0, 0) x "a"_cf(0, 0) x "a"_cf(0, 0)] -(0)-> "a"_cf(0, 0)
  "node" :: ["b"_cf(4, 0) x "a"_cf(4, 0) x "a"_cf(4, 0)] -(4)-> "a"_cf(4, 0)
  "node" :: ["b"_cf(14, 0) x "a"_cf(14, 0) x "a"_cf(14, 0)] -(14)-> "a"_cf(14, 0)
  "node" :: ["b"_cf(9, 0) x "a"_cf(9, 0) x "a"_cf(9, 0)] -(9)-> "a"_cf(9, 0)
  "node" :: ["b"_cf(1, 0) x "a"_cf(1, 0) x "a"_cf(1, 0)] -(1)-> "a"_cf(1, 0)
  "subtrees" :: ["a"_cf(4, 0)] -(0)-> "c"_cf(3, 1)
  "subtrees" :: ["a"_cf(14, 0)] -(0)-> "c"_cf(4, 4)
  "subtrees" :: ["a"_cf(9, 0)] -(1)-> "c"_cf(0, 0)
  "subtrees" :: ["a"_cf(1, 0)] -(1)-> "c"_cf(0, 0)
  "subtrees#1" :: ["a"_cf(4, 0)] -(0)-> "c"_cf(3, 1)
  "subtrees#1" :: ["a"_cf(14, 0)] -(0)-> "c"_cf(5, 4)
  "subtrees#1" :: ["a"_cf(9, 0)] -(1)-> "c"_cf(0, 0)
  "subtrees#1" :: ["a"_cf(1, 0)] -(1)-> "c"_cf(0, 0)
  "subtrees#2" :: ["c"_cf(3, 1) x "a"_cf(0, 0) x "a"_cf(4, 0) x "b"_cf(0, 0)] -(4)-> "c"_cf(3, 1)
  "subtrees#2" :: ["c"_cf(4, 4) x "a"_cf(0, 0) x "a"_cf(14, 0) x "b"_cf(0, 0)] -(10)-> "c"_cf(8, 4)
  "subtrees#2" :: ["c"_cf(0, 0) x "a"_cf(0, 0) x "a"_cf(9, 0) x "b"_cf(0, 0)] -(9)-> "c"_cf(1, 0)
  "subtrees#2" :: ["c"_cf(0, 0) x "a"_cf(0, 0) x "a"_cf(1, 0) x "b"_cf(0, 0)] -(1)-> "c"_cf(0, 0)
  "subtrees#3" :: ["c"_cf(1, 1) x "c"_cf(1, 1) x "a"_cf(0, 0) x "a"_cf(0, 0) x "b"_cf(0, 0)] -(4)-> "c"_cf(3, 1)
  "subtrees#3" :: ["c"_cf(4, 4) x "c"_cf(4, 4) x "a"_cf(0, 0) x "a"_cf(0, 0) x "b"_cf(0, 0)] -(10)-> "c"_cf(8, 4)
  "subtrees#3" :: ["c"_cf(0, 0) x "c"_cf(0, 0) x "a"_cf(0, 0) x "a"_cf(0, 0) x "b"_cf(0, 0)] -(5)-> "c"_cf(1, 0)
  "subtrees#3" :: ["c"_cf(0, 0) x "c"_cf(0, 0) x "a"_cf(0, 0) x "a"_cf(0, 0) x "b"_cf(0, 0)] -(0)-> "c"_cf(0, 0)


Base Constructors:
------------------
  "\"cons\"_c" :: ["a"(0, 0) x "c"(0, 0)] -(1)-> "c"(1, 0)
  "\"cons\"_c" :: ["a"(0, 0) x "c"(1, 1)] -(0)-> "c"(0, 1)
  "\"leaf\"_a" :: [] -(0)-> "a"(1, 0)
  "\"leaf\"_a" :: [] -(0)-> "a"(0, 1)
  "\"nil\"_c" :: [] -(0)-> "c"(1, 0)
  "\"nil\"_c" :: [] -(0)-> "c"(0, 1)
  "\"node\"_a" :: ["b"(1, 0) x "a"(1, 0) x "a"(1, 0)] -(1)-> "a"(1, 0)
  "\"node\"_a" :: ["b"(0, 1) x "a"(1, 1) x "a"(1, 1)] -(1)-> "a"(0, 1)