(VAR x y z )
(RULES 
        cond1(true, x, y, z) -> cond2(gr(x, 0), x, y, z)
        cond2(true, x, y, z) -> cond1(or(gr(x, z), gr(y, z)), p(x), y, z)
        cond2(false, x, y, z) -> cond3(gr(y, 0), x, y, z)
        cond3(true, x, y, z) -> cond1(or(gr(x, z), gr(y, z)), x, p(y), z)
        cond3(false, x, y, z) -> cond1(or(gr(x, z), gr(y, z)), x, y, z)
        gr(0, x) -> false
        gr(s(x), 0) -> true
        gr(s(x), s(y)) -> gr(x, y)
        or(false, false) -> false
        or(true, x) -> true
        or(x, true) -> true
        p(0) -> 0
        p(s(x)) -> x
        
)