(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)))
        active(from(X)) -> from(active(X))
        active(cons(X1, X2)) -> cons(active(X1), X2)
        active(s(X)) -> s(active(X))
        active(sel(X1, X2)) -> sel(active(X1), X2)
        active(sel(X1, X2)) -> sel(X1, active(X2))
        active(minus(X1, X2)) -> minus(active(X1), X2)
        active(minus(X1, X2)) -> minus(X1, active(X2))
        active(quot(X1, X2)) -> quot(active(X1), X2)
        active(quot(X1, X2)) -> quot(X1, active(X2))
        active(zWquot(X1, X2)) -> zWquot(active(X1), X2)
        active(zWquot(X1, X2)) -> zWquot(X1, active(X2))
        from(mark(X)) -> mark(from(X))
        cons(mark(X1), X2) -> mark(cons(X1, X2))
        s(mark(X)) -> mark(s(X))
        sel(mark(X1), X2) -> mark(sel(X1, X2))
        sel(X1, mark(X2)) -> mark(sel(X1, X2))
        minus(mark(X1), X2) -> mark(minus(X1, X2))
        minus(X1, mark(X2)) -> mark(minus(X1, X2))
        quot(mark(X1), X2) -> mark(quot(X1, X2))
        quot(X1, mark(X2)) -> mark(quot(X1, X2))
        zWquot(mark(X1), X2) -> mark(zWquot(X1, X2))
        zWquot(X1, mark(X2)) -> mark(zWquot(X1, X2))
        proper(from(X)) -> from(proper(X))
        proper(cons(X1, X2)) -> cons(proper(X1), proper(X2))
        proper(s(X)) -> s(proper(X))
        proper(sel(X1, X2)) -> sel(proper(X1), proper(X2))
        proper(0) -> ok(0)
        proper(minus(X1, X2)) -> minus(proper(X1), proper(X2))
        proper(quot(X1, X2)) -> quot(proper(X1), proper(X2))
        proper(zWquot(X1, X2)) -> zWquot(proper(X1), proper(X2))
        proper(nil) -> ok(nil)
        from(ok(X)) -> ok(from(X))
        cons(ok(X1), ok(X2)) -> ok(cons(X1, X2))
        s(ok(X)) -> ok(s(X))
        sel(ok(X1), ok(X2)) -> ok(sel(X1, X2))
        minus(ok(X1), ok(X2)) -> ok(minus(X1, X2))
        quot(ok(X1), ok(X2)) -> ok(quot(X1, X2))
        zWquot(ok(X1), ok(X2)) -> ok(zWquot(X1, X2))
        top(mark(X)) -> top(proper(X))
        top(ok(X)) -> top(active(X))
        
)