(VAR x y z )
(RULES 
        max(L(x)) -> x
        max(N(L(0), L(y))) -> y
        max(N(L(s(x)), L(s(y)))) -> s(max(N(L(x), L(y))))
        max(N(L(x), N(y, z))) -> max(N(L(x), L(max(N(y, z)))))
        
)