TRS:
 {      -(x, 0()) -> x,
    -(s(x), s(y)) -> -(x, y),
      min(x, 0()) -> 0(),
      min(0(), y) -> 0(),
  min(s(x), s(y)) -> s(min(x, y)),
       twice(0()) -> 0(),
      twice(s(x)) -> s(s(twice(x))),
    f(s(x), s(y)) -> f(-(y, min(x, y)), s(twice(min(x, y)))),
    f(s(x), s(y)) -> f(-(x, min(x, y)), s(twice(min(x, y))))}
 Fail