WORST_CASE(?,O(n^1))

Solution:
---------

  Cons :: [A(15) x A(15)] -(15)-> A(15)
  Cons :: [A(1) x A(1)] -(1)-> A(1)
  Nil :: [] -(0)-> A(15)
  Nil :: [] -(0)-> A(7)
  fleft_op_e_xs_1 :: [] -(0)-> A(13)
  fleft_op_e_xs_1 :: [] -(0)-> A(14)
  foldr#3 :: [A(15)] -(8)-> A(14)
  main :: [A(15)] -(1)-> A(0)
  rev_l :: [] -(0)-> A(6)
  rev_l :: [] -(0)-> A(14)
  rev_l#2 :: [A(1) x A(8)] -(4)-> A(1)
  step_x_f :: [A(13) x A(13) x A(13)] -(13)-> A(13)
  step_x_f :: [A(14) x A(14) x A(14)] -(14)-> A(14)
  step_x_f#1 :: [A(6) x A(9) x A(13) x A(1)] -(6)-> A(1)


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

  Cons :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
  Nil :: [] -(0)-> A_cf(0)
  fleft_op_e_xs_1 :: [] -(0)-> A_cf(0)
  foldr#3 :: [A_cf(0)] -(0)-> A_cf(0)
  rev_l :: [] -(0)-> A_cf(0)
  rev_l#2 :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
  step_x_f :: [A_cf(0) x A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
  step_x_f#1 :: [A_cf(0) x A_cf(0) x A_cf(0) x A_cf(0)] -(0)-> A_cf(0)


Base Constructors:
------------------
  Cons_A :: [A(1) x A(1)] -(1)-> A(1)
  Nil_A :: [] -(0)-> A(1)
  fleft_op_e_xs_1_A :: [] -(0)-> A(1)
  rev_l_A :: [] -(0)-> A(1)
  step_x_f_A :: [A(0) x A(0) x A(0)] -(1)-> A(1)