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 NewClass {
    public static void main(String[]args){
      long t = 0,n;
   Scanner input = new Scanner(System.in);
        long a,b,c,d,sum=0;
      a=input.nextInt();
      b=input.nextInt();
      c=input.nextInt();
      sum=a-b;
      
        if(sum>c) {
        System.out.println(c+1);
    }
        else{
            System.out.println(sum);
  }
}
    }


