Distinct Routes

A game consists of n rooms and m teleporters. At the beginning of each day, you start in room 1 and you have to reach room n. You can use each teleporter at most once during the game. How many days can you play if you choose your routes optimally? Input The first input line has two integers n and m: the number of rooms and teleporters. The rooms are numbered 1,2,\dots,n. After this, there are