WORST_CASE(?,O(n^2))

Solution:
---------

  0 :: [] -(0)-> A(6, 3)
  0 :: [] -(0)-> A(9, 3)
  0 :: [] -(0)-> A(13, 5)
  a__add :: [A(6, 3) x A(9, 3)] -(7)-> A(6, 3)
  a__from :: [A(9, 3)] -(8)-> A(6, 3)
  a__fst :: [A(6, 3) x A(9, 3)] -(7)-> A(6, 3)
  a__len :: [A(6, 3)] -(7)-> A(6, 3)
  add :: [A(9, 3) x A(12, 3)] -(9)-> A(9, 3)
  add :: [A(0, 0) x A(0, 0)] -(0)-> A(0, 0)
  add :: [A(6, 3) x A(9, 3)] -(6)-> A(6, 3)
  cons :: [A(9, 3) x A(0, 0)] -(9)-> A(9, 3)
  cons :: [A(6, 3) x A(0, 0)] -(6)-> A(6, 3)
  from :: [A(12, 3)] -(9)-> A(9, 3)
  from :: [A(0, 0)] -(0)-> A(0, 0)
  from :: [A(9, 3)] -(6)-> A(6, 3)
  fst :: [A(9, 3) x A(12, 3)] -(9)-> A(9, 3)
  fst :: [A(0, 0) x A(0, 0)] -(0)-> A(0, 0)
  fst :: [A(6, 3) x A(9, 3)] -(6)-> A(6, 3)
  len :: [A(9, 3)] -(9)-> A(9, 3)
  len :: [A(0, 0)] -(0)-> A(0, 0)
  len :: [A(6, 3)] -(6)-> A(6, 3)
  mark :: [A(9, 3)] -(1)-> A(6, 3)
  nil :: [] -(0)-> A(6, 3)
  nil :: [] -(0)-> A(9, 3)
  nil :: [] -(0)-> A(13, 5)
  s :: [A(0, 0)] -(0)-> A(6, 3)
  s :: [A(0, 0)] -(0)-> A(9, 3)
  s :: [A(0, 0)] -(0)-> A(2, 11)
  s :: [A(0, 0)] -(0)-> A(12, 13)
  s :: [A(0, 0)] -(0)-> A(11, 15)
  s :: [A(0, 0)] -(0)-> A(8, 10)


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

  0 :: [] -(0)-> A_cf(0, 0)
  0 :: [] -(0)-> A_cf(3, 0)
  0 :: [] -(0)-> A_cf(3, 2)
  a__add :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
  a__add :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
  a__from :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  a__from :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
  a__fst :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
  a__fst :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
  a__len :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  a__len :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
  add :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
  add :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
  cons :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
  cons :: [A_cf(3, 0) x A_cf(0, 0)] -(3)-> A_cf(3, 0)
  from :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  from :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
  from :: [A_cf(1, 1)] -(0)-> A_cf(0, 1)
  from :: [A_cf(2, 2)] -(0)-> A_cf(0, 2)
  fst :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
  fst :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
  len :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  len :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
  mark :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  mark :: [A_cf(3, 0)] -(0)-> A_cf(3, 0)
  nil :: [] -(0)-> A_cf(0, 0)
  nil :: [] -(0)-> A_cf(3, 0)
  nil :: [] -(0)-> A_cf(3, 2)
  s :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  s :: [A_cf(0, 0)] -(0)-> A_cf(3, 0)
  s :: [A_cf(0, 0)] -(0)-> A_cf(1, 4)
  s :: [A_cf(0, 0)] -(0)-> A_cf(4, 4)
  s :: [A_cf(0, 0)] -(0)-> A_cf(12, 12)
  s :: [A_cf(0, 0)] -(0)-> A_cf(7, 8)
  s :: [A_cf(0, 0)] -(0)-> A_cf(2, 12)
  s :: [A_cf(0, 0)] -(0)-> A_cf(5, 8)
  s :: [A_cf(0, 0)] -(0)-> A_cf(3, 10)
  s :: [A_cf(0, 0)] -(0)-> A_cf(9, 10)
  s :: [A_cf(0, 0)] -(0)-> A_cf(14, 14)
  s :: [A_cf(0, 0)] -(0)-> A_cf(6, 6)
  s :: [A_cf(0, 0)] -(0)-> A_cf(3, 2)


Base Constructors:
------------------
  0_A :: [] -(0)-> A(1, 0)
  0_A :: [] -(0)-> A(0, 1)
  add_A :: [A(1, 0) x A(1, 0)] -(1)-> A(1, 0)
  add_A :: [A(0, 1) x A(1, 1)] -(0)-> A(0, 1)
  cons_A :: [A(1, 0) x A(0, 0)] -(1)-> A(1, 0)
  cons_A :: [A(0, 1) x A(0, 0)] -(0)-> A(0, 1)
  from_A :: [A(1, 0)] -(1)-> A(1, 0)
  from_A :: [A(1, 1)] -(0)-> A(0, 1)
  fst_A :: [A(1, 0) x A(1, 0)] -(1)-> A(1, 0)
  fst_A :: [A(0, 1) x A(1, 1)] -(0)-> A(0, 1)
  len_A :: [A(1, 0)] -(1)-> A(1, 0)
  len_A :: [A(0, 1)] -(0)-> A(0, 1)
  nil_A :: [] -(0)-> A(1, 0)
  nil_A :: [] -(0)-> A(0, 1)
  s_A :: [A(0, 0)] -(0)-> A(1, 0)
  s_A :: [A(0, 0)] -(0)-> A(0, 1)