TRS:
 {                 from(X) -> cons(X, n__from(s(X))),
            after(0(), XS) -> XS,
  after(s(N), cons(X, XS)) -> after(N, activate(XS)),
                   from(X) -> n__from(X),
      activate(n__from(X)) -> from(X),
               activate(X) -> X}
 Fail