the number of position

Description
Jesse 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 less than B people standing behind him.

Find the number of different positions Jesse 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.

Sample Input
Copy sample input to clipboard
10 2 4
Sample Output
4

#include<iostream>
using namespace std;

int main()
{
    int num;
    while(cin >> num){
        int a, b;
        cin >> a >> b ;
        int result = num - a - b;
        cout << result << endl;
    }

    return 0;
}

we know that Jesse stands in line of people, and there are no less than A people standing in front of him, and no less than B people standing behind him.
so when there are exactly A and B in the problem, we can get the max.
then problem is solved