(VAR x )
(RULES 
        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
        
)