TRS:
 {    cond(true(), x) -> cond(and(even(x), gr(x, 0())), p(x)),
      and(x, false()) -> false(),
      and(false(), x) -> false(),
  and(true(), true()) -> true(),
            even(0()) -> true(),
         even(s(0())) -> false(),
        even(s(s(x))) -> even(x),
           gr(0(), x) -> false(),
        gr(s(x), 0()) -> true(),
     gr(s(x), s(y())) -> gr(x, y()),
               p(0()) -> 0(),
              p(s(x)) -> x}
 Fail