WORST_CASE(?,O(n^1))

Solution:
---------

  0 :: [] -(0)-> A(1)
  0 :: [] -(0)-> A(0)
  S :: [A(1)] -(1)-> A(1)
  S :: [A(0)] -(0)-> A(0)
  even :: [A(1)] -(1)-> A(0)
  odd :: [A(1)] -(1)-> A(0)


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

  0 :: [] -(0)-> A_cf(0)
  S :: [A_cf(0)] -(0)-> A_cf(0)
  even :: [A_cf(0)] -(0)-> A_cf(0)
  odd :: [A_cf(0)] -(0)-> A_cf(0)