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.
import java.util.Scanner;
public class One
{
    static public void main (String[] args)
    {
        int n = 0, a = 0, b = 0;
        Scanner in = new Scanner(System.in);
        n = in.nextInt();
        a = in.nextInt();
        b = in.nextInt();
        {
            int r = n - a;
            int t = r - b;
            
            if (t > 1)
            {
                t--;
                r -= t;
            }
            System.out.println(r);
        }
    }
}