(VAR X) (RULES f(0) -> cons(0,n__f(n__s(n__0))) f(s(0)) -> f(p(s(0))) p(s(0)) -> 0 f(X) -> n__f(X) s(X) -> n__s(X) 0 -> n__0 activate(n__f(X)) -> f(activate(X)) activate(n__s(X)) -> s(activate(X)) activate(n__0) -> 0 activate(X) -> X )