(VAR N X X1 X2 XS Y YS )
(RULES 
        active(from(X)) -> mark(cons(X, from(s(X))))
        active(sel(0, cons(X, XS))) -> mark(X)
        active(sel(s(N), cons(X, XS))) -> mark(sel(N, XS))
        active(minus(X, 0)) -> mark(0)
        active(minus(s(X), s(Y))) -> mark(minus(X, Y))
        active(quot(0, s(Y))) -> mark(0)
        active(quot(s(X), s(Y))) -> mark(s(quot(minus(X, Y), s(Y))))
        active(zWquot(XS, nil)) -> mark(nil)
        active(zWquot(nil, XS)) -> mark(nil)
        active(zWquot(cons(X, XS), cons(Y, YS))) -> mark(cons(quot(X, Y), zWquot(XS, YS)))
        mark(from(X)) -> active(from(mark(X)))
        mark(cons(X1, X2)) -> active(cons(mark(X1), X2))
        mark(s(X)) -> active(s(mark(X)))
        mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2)))
        mark(0) -> active(0)
        mark(minus(X1, X2)) -> active(minus(mark(X1), mark(X2)))
        mark(quot(X1, X2)) -> active(quot(mark(X1), mark(X2)))
        mark(zWquot(X1, X2)) -> active(zWquot(mark(X1), mark(X2)))
        mark(nil) -> active(nil)
        from(mark(X)) -> from(X)
        from(active(X)) -> from(X)
        cons(mark(X1), X2) -> cons(X1, X2)
        cons(X1, mark(X2)) -> cons(X1, X2)
        cons(active(X1), X2) -> cons(X1, X2)
        cons(X1, active(X2)) -> cons(X1, X2)
        s(mark(X)) -> s(X)
        s(active(X)) -> s(X)
        sel(mark(X1), X2) -> sel(X1, X2)
        sel(X1, mark(X2)) -> sel(X1, X2)
        sel(active(X1), X2) -> sel(X1, X2)
        sel(X1, active(X2)) -> sel(X1, X2)
        minus(mark(X1), X2) -> minus(X1, X2)
        minus(X1, mark(X2)) -> minus(X1, X2)
        minus(active(X1), X2) -> minus(X1, X2)
        minus(X1, active(X2)) -> minus(X1, X2)
        quot(mark(X1), X2) -> quot(X1, X2)
        quot(X1, mark(X2)) -> quot(X1, X2)
        quot(active(X1), X2) -> quot(X1, X2)
        quot(X1, active(X2)) -> quot(X1, X2)
        zWquot(mark(X1), X2) -> zWquot(X1, X2)
        zWquot(X1, mark(X2)) -> zWquot(X1, X2)
        zWquot(active(X1), X2) -> zWquot(X1, X2)
        zWquot(X1, active(X2)) -> zWquot(X1, X2)
        
)