Codeforces 124A

题目链接：http://codeforces.com/problemset/problem/124/A

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.

题解：减去面前的与后面的再比较

#include <iostream>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
using namespace std;
#define N 100010
int main()
{
    int n,a,b;
    while(cin>>n>>a>>b){
        int s=n-a;
        if(s>b) s=b+1;
        cout<<s<<endl;    
    }
    return 0;
}