Rick and Morty

Rick and Morty are playing a video game called "Shoot 'em all". In this game, a player shoots his opponent and his opponent shoot him back until one of them is dead. When one of them is dead the game end and the number of shooted bullets by each player are shown on the screen.

Rick knows that he always shoots more bullets than Morty. Now he is wondering exactly how many bullets he shot more
than Morty.

Rick is so busy playing this game. So he wants you to calculate the number of bullets he shots more than Morthy. He will give you the number of the bullet he shot which is N and the number of bullets Morty shots which is M.

Input

Input will contain two integer numbers N and M (1<=M<N<=1000).

Output

Print only one integer. The result of (N-M).

Sample

Input	Output
5 3	2