WORST_CASE(?,O(n^1))

Solution:
---------

  0 :: [] -(0)-> A(5)
  0 :: [] -(0)-> A(4)
  0 :: [] -(0)-> A(7)
  0 :: [] -(0)-> A(13)
  average :: [A(5) x A(4)] -(3)-> A(0)
  s :: [A(5)] -(5)-> A(5)
  s :: [A(4)] -(4)-> A(4)
  s :: [A(0)] -(0)-> A(0)


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

  0 :: [] -(0)-> A_cf(0)
  average :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
  s :: [A_cf(0)] -(0)-> A_cf(0)


Base Constructors:
------------------
  0_A :: [] -(0)-> A(1)
  s_A :: [A(1)] -(1)-> A(1)