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 Main {

    private static Scanner scanner = new Scanner(System.in);
    
    public static void main(String[] args) {
        
        int n;
        int a;
        int b;
        
        n = scanner.nextInt();
        a = scanner.nextInt();
        b = scanner.nextInt();
        
        if ((n - a) < (b + 1))
        System.out.println(n - a);
        else
            System.out.println(b + 1);
    }
    
}