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;

/**
 *
 * @author Sara
 */
public class JavaApplication4 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        {
           
            int n = 5, a = 2, b = 3, c, r;
            Scanner read = new Scanner(System.in);
            n = read.nextInt();
            a = read.nextInt();
            b = read.nextInt();
            if(n<0||a<0||b<0){
                System.out.println("wrong input");
                System.exit(0);
            }

            c = n - a - 1;
            if (c > b) {
                r = b + 1;
            } else {
                r = c + 1;
            }
            System.out.println(r);

        }
    }

}