TRS:
 {    lt(0(), s(x)) -> true(),
         lt(x, 0()) -> false(),
     lt(s(x), s(y)) -> lt(x, y),
             fac(x) -> help(x, 0()),
         help(x, c) -> if(lt(c, x), x, c),
   if(true(), x, c) -> times(s(c), help(x, s(c))),
  if(false(), x, c) -> s(0())}
 Fail