TRS:
 {      fac(0()) -> 1(),
       fac(s(x)) -> *(s(x), fac(x)),
   floop(0(), y) -> y,
  floop(s(x), y) -> floop(x, *(s(x), y)),
       *(x, 0()) -> 0(),
      *(x, s(y)) -> +(*(x, y), x),
       +(x, 0()) -> x,
      +(x, s(y)) -> s(+(x, y)),
             1() -> s(0()),
        fac(0()) -> s(0())}
 Fail