MAYBE

We are left with following problem, upon which TcT provides the
certificate MAYBE.

Strict Trs:
  { a__f(X) -> cons(mark(X), f(g(X)))
  , a__f(X) -> f(X)
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(f(X)) -> a__f(mark(X))
  , mark(g(X)) -> a__g(mark(X))
  , mark(0()) -> 0()
  , mark(s(X)) -> s(mark(X))
  , mark(sel(X1, X2)) -> a__sel(mark(X1), mark(X2))
  , a__g(X) -> g(X)
  , a__g(0()) -> s(0())
  , a__g(s(X)) -> s(s(a__g(mark(X))))
  , a__sel(X1, X2) -> sel(X1, X2)
  , a__sel(0(), cons(X, Y)) -> mark(X)
  , a__sel(s(X), cons(Y, Z)) -> a__sel(mark(X), mark(Z)) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..