Winter is here

Jon Snow, former Commander of the Night's Watch is getting ready for a war against the Army of the Dead. But before he leaves, his sister Arya gives him a small puzzle. She gives him $N$ numbers and asks him to check if the number $M$ is present in the list. He has to find it in the shortest time possible, given that the numbers are already sorted. Sounds easy? Then help Jon find it. ###Input: -