Mail Delivery

Your task is to deliver mail to the inhabitants of a city. For this reason, you want to find a route whose starting and ending point are the post office, and that goes through every street exactly once. Input The first input line has two integers n and m: the number of crossings and streets. The crossings are numbered 1,\,2,\ldots,\,n, and the post office is located at crossing 1. After that, t