WORST_CASE(?,O(n^2))

Solution:
---------

  + :: [A(0, 0) x A(1, 0)] -(1)-> A(0, 0)
  0 :: [] -(0)-> A(3, 1)
  0 :: [] -(0)-> A(1, 0)
  0 :: [] -(0)-> A(0, 0)
  s :: [A(4, 1)] -(3)-> A(3, 1)
  s :: [A(1, 0)] -(1)-> A(1, 0)
  s :: [A(0, 0)] -(0)-> A(0, 0)
  sum :: [A(3, 1)] -(1)-> A(0, 0)


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

  + :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
  0 :: [] -(0)-> A_cf(0, 0)
  s :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
  sum :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)