MAYBE

'Pop* (timeout of 60.0 seconds)'
--------------------------------
Answer:           MAYBE
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  fst(0(), Z) -> nil()
     , fst(s(X), cons(Y, Z)) -> cons(Y, fst(X, Z))
     , from(X) -> cons(X, from(s(X)))
     , add(0(), X) -> X
     , add(s(X), Y) -> s(add(X, Y))
     , len(nil()) -> 0()
     , len(cons(X, Z)) -> s(len(Z))}

Proof Output:    
  The input cannot be shown compatible