MAYBE

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

Strict Trs:
  { plus(x, s(s(y))) -> s(plus(s(x), y))
  , plus(s(s(x)), y) -> s(plus(x, s(y)))
  , plus(s(0()), y) -> s(y)
  , plus(0(), y) -> y
  , ack(s(x), s(y)) -> ack(x, plus(y, ack(s(x), y)))
  , ack(s(x), 0()) -> ack(x, s(0()))
  , ack(0(), y) -> s(y) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..