WORST_CASE(?,O(n^1))

Solution:
---------

  f :: [A(12) x A(9) x A(3)] -(15)-> A(0)
  s :: [A(12)] -(12)-> A(12)
  s :: [A(3)] -(3)-> A(3)


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

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


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