TRS:
 {                 app(nil(), YS) -> YS,
             app(cons(X, XS), YS) -> cons(X, app(XS, YS)),
                          from(X) -> cons(X, from(s(X))),
                 zWadr(nil(), YS) -> nil(),
                 zWadr(XS, nil()) -> nil(),
  zWadr(cons(X, XS), cons(Y, YS)) -> cons(app(Y, cons(X, nil())), zWadr(XS, YS)),
                        prefix(L) -> cons(nil(), zWadr(L, prefix(L)))}
 Fail