WORST_CASE(?,O(n^1))

Solution:
---------

  a :: [] -(0)-> A(0)
  a :: [] -(0)-> A(2)
  a__f :: [A(0)] -(1)-> A(0)
  c :: [A(2)] -(2)-> A(2)
  c :: [A(0)] -(0)-> A(0)
  f :: [A(0)] -(0)-> A(0)
  f :: [A(2)] -(2)-> A(2)
  g :: [A(2)] -(2)-> A(2)
  g :: [A(0)] -(0)-> A(0)
  mark :: [A(2)] -(1)-> A(0)


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

  a :: [] -(0)-> A_cf(0)
  a__f :: [A_cf(0)] -(0)-> A_cf(0)
  c :: [A_cf(0)] -(0)-> A_cf(0)
  f :: [A_cf(0)] -(0)-> A_cf(0)
  g :: [A_cf(0)] -(0)-> A_cf(0)
  mark :: [A_cf(0)] -(0)-> A_cf(0)