This is a difficult question to answer unless you know why they rejected you. If you do not know why you didn’t get it, then it is probably worth having another go. However, if you do know why they rejected you then you need to make sure that you have addressed the issue that they had a problem with before applying again. You will have different candidates to compete with this time so even if you were not the best of the lot last time, it does not mean you will not be this time.