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 pozition 
{

    public static void main(String[] args) 
    {
        Scanner in = new Scanner(System.in);
        int N = in.nextInt();
        int d0 = in.nextInt();
        int posle = in.nextInt();
        if((d0+posle) < N-1)
        {
            int vrem = d0+posle+1;
            int vrem2 = N-vrem;
            d0 = vrem2+d0;
        }
        N = N - d0;
        System.out.print(N);
    }

}
