MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          a__add(X1,X2) -> add(X1,X2)
          a__add(0(),X) -> mark(X)
          a__add(s(X),Y) -> s(a__add(mark(X),mark(Y)))
          a__fib(N) -> a__sel(mark(N),a__fib1(s(0()),s(0())))
          a__fib(X) -> fib(X)
          a__fib1(X,Y) -> cons(mark(X),fib1(Y,add(X,Y)))
          a__fib1(X1,X2) -> fib1(X1,X2)
          a__sel(X1,X2) -> sel(X1,X2)
          a__sel(0(),cons(X,XS)) -> mark(X)
          a__sel(s(N),cons(X,XS)) -> a__sel(mark(N),mark(XS))
          mark(0()) -> 0()
          mark(add(X1,X2)) -> a__add(mark(X1),mark(X2))
          mark(cons(X1,X2)) -> cons(mark(X1),X2)
          mark(fib(X)) -> a__fib(mark(X))
          mark(fib1(X1,X2)) -> a__fib1(mark(X1),mark(X2))
          mark(s(X)) -> s(mark(X))
          mark(sel(X1,X2)) -> a__sel(mark(X1),mark(X2))
      - Signature:
          {a__add/2,a__fib/1,a__fib1/2,a__sel/2,mark/1} / {0/0,add/2,cons/2,fib/1,fib1/2,s/1,sel/2}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {a__add,a__fib,a__fib1,a__sel,mark} and constructors {0
          ,add,cons,fib,fib1,s,sel}
  + Applied Processor:
      NaturalPI {shape = Mixed 3, restrict = NoRestrict, uargs = UArgs, urules = URules, selector = Nothing}
  + Details:
      Incompatible
MAYBE