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 JavaApplication1 {
    static int xc[][]=new int[2][2];
    public static void main(String[] args) {
        Scanner a=new Scanner(System.in);
        int n=a.nextInt();
        int x=a.nextInt();
        int z=a.nextInt();
        if(n<x || n<z){
            System.out.println(0);
        }
        else{
            int g=0;
            for(int i=x+1;i<=n;i++){
                if(i+z>=n){
                    g=n-i+1;
                    break;
                }
            }
            System.out.println(g);
        }
    }   
}

  		 	 				      			 	  		