TRS: { a__zeros() -> cons(0(), zeros()), a__tail(cons(X, XS)) -> mark(XS), mark(zeros()) -> a__zeros(), mark(tail(X)) -> a__tail(mark(X)), mark(cons(X1, X2)) -> cons(mark(X1), X2), mark(0()) -> 0(), a__zeros() -> zeros(), a__tail(X) -> tail(X)} Fail