A. The number of positions

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 n, a 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.

#include<iostream>
using namespace std;
int main()
{
    int n,a,b;
    while(cin>>n>>a>>b)
    {
        int cnt=;
        for(int i=;i<n;i++)
        {
            if(i>=a&&n-i-<=b)
                cnt++;
        }
        cout<<cnt<<endl;
    }
    return ;
}