(VAR x y z )
(RULES 
        norm(nil) -> 0
        norm(g(x, y)) -> s(norm(x))
        f(x, nil) -> g(nil, x)
        f(x, g(y, z)) -> g(f(x, y), z)
        rem(nil, y) -> nil
        rem(g(x, y), 0) -> g(x, y)
        rem(g(x, y), s(z)) -> rem(x, z)
        
)