WORST_CASE(?,O(n^1))

Solution:
---------

  0 :: [] -(0)-> a(4)
  0 :: [] -(0)-> a(12)
  0 :: [] -(0)-> a(6)
  bits :: [a(4)] -(1)-> a(0)
  half :: [a(4)] -(1)-> a(6)
  s :: [a(4)] -(4)-> a(4)
  s :: [a(6)] -(6)-> a(6)
  s :: [a(2)] -(2)-> a(2)
  s :: [a(0)] -(0)-> a(0)


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

  0 :: [] -(0)-> a_cf(0)
  bits :: [a_cf(0)] -(0)-> a_cf(0)
  half :: [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)