MAYBE

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

Strict Trs:
  { a(x1) -> b(c(x1))
  , a(b(x1)) -> b(a(x1))
  , a(c(x1)) -> c(a(x1))
  , d(c(x1)) -> d(a(x1)) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..