(VAR m n u v x y z )
(RULES 
        f(true, x, y, z) -> f(gt(x, plus(y, z)), x, s(y), z)
        f(true, x, y, z) -> f(gt(x, plus(y, z)), x, y, s(z))
        plus(n, 0) -> n
        plus(n, s(m)) -> s(plus(n, m))
        gt(0, v) -> false
        gt(s(u), 0) -> true
        gt(s(u), s(v)) -> gt(u, v)
        
)