(VAR x1 )
(RULES 
        R(x1) -> r(x1)
        r(p(x1)) -> p(p(r(P(x1))))
        r(r(x1)) -> x1
        r(P(P(x1))) -> P(P(r(x1)))
        p(P(x1)) -> x1
        P(p(x1)) -> x1
        r(R(x1)) -> x1
        R(r(x1)) -> x1
        
)