(VAR N X XS Y )
(RULES 
        sel(s(N), cons(X)) -> sel(N, XS)
        from(X) -> cons(X)
        sel(0, cons(X)) -> X
        minus(X, 0) -> 0
        minus(s(X), s(Y)) -> minus(X, Y)
        quot(0, s(Y)) -> 0
        quot(s(X), s(Y)) -> s(quot(minus(X, Y), s(Y)))
        zWquot(XS, nil) -> nil
        zWquot(nil, XS) -> nil
        zWquot(cons(X), cons(Y)) -> cons(quot(X, Y))
        
)