MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          a__f(X) -> f(X)
          a__f(f(a())) -> a__f(g(f(a())))
          mark(a()) -> a()
          mark(f(X)) -> a__f(X)
          mark(g(X)) -> g(mark(X))
      - Signature:
          {a__f/1,mark/1} / {a/0,f/1,g/1}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {a__f,mark} and constructors {a,f,g}
  + Applied Processor:
      NaturalPI {shape = Mixed 3, restrict = NoRestrict, uargs = UArgs, urules = URules, selector = Nothing}
  + Details:
      Incompatible
MAYBE