MAYBE
MAYBE
TRS:
 {
            first(0(), X) -> nil(),
  first(s(X), cons(Y, Z)) -> cons(Y, first(X, Z)),
                  from(X) -> cons(X, from(s(X)))
 }
 DUP: We consider a duplicating system.
  Trs:
   {
              first(0(), X) -> nil(),
    first(s(X), cons(Y, Z)) -> cons(Y, first(X, Z)),
                    from(X) -> cons(X, from(s(X)))
   }
  Fail