浙南联合训练赛 H - The number of positions

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 n, a and b (0 ≤ a, b < n ≤ 100).

Output

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

Examples

Input

3 1 1

Output

2

Input

5 2 3

Output

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.

#include <iostream>
#include <stdio.h>
#include <algorithm>
using namespace std;

int main()
{
   int n,a,b;
   scanf("%d %d %d",&n,&a,&b);
   printf("%d\n",min(n-a,b+1));
}