In the supermarket, $N$ people are queuing up in front of the cashier.

Bob is one of the people inside the queue, but he doesn't know which position he is currently at. He only knows that there are $A$ people behind him.

How many people are in front of him?

Input

The only line consists of $2$ integers $N$ and $A$.

Output

The number of people in front of Bob.

Constraints

For all test cases: $1 \le N \le 10^{6}$, $0 \le A < 10^{6}$.