## Algorithm

A. The number of positions
time limit per test
0.5 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Petr stands in line of n people, but he doesn't know exactly which position he occupies. He can say that there are no less than a people standing in front of him and no more than b people standing behind him. Find the number of different positions Petr can occupy.

Input

The only line contains three integers na and b (0 ≤ a, b < n ≤ 100).

Output

Print the single number — the number of the sought positions.

Examples
input
Copy
`3 1 1`
output
Copy
`2`
input
Copy
`5 2 3`
output
Copy
`3`
Note

The possible positions in the first sample are: 2 and 3 (if we number the positions starting with 1).

In the second sample they are 3, 4 and 5.

## Code Examples

### #1 Code Example with C++ Programming

```Code - C++ Programming```

``````#include <cstdio>
#include <iostream>

int main(){
int n, a, b; scanf("%d %d %d", &n, &a, &b);
printf("%d\n", std::min(n - a,b + 1));
return 0;
}``````
Copy The Code &

Input

cmd
3 1 1

Output

cmd
2