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 P124A
{

    public static void main(String[] args)
    {
        Scanner inScanner = new Scanner(System.in);
        int n = inScanner.nextInt();
        int a = inScanner.nextInt();
        int b = inScanner.nextInt();
        int max1 = n - a;
        int max2 = b + 1;
        System.out.println(Math.min(max1, max2));
    }
}
