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 YoungPhysicist {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner s = new Scanner(System.in);
        int a = 0 , b = 0 , c = 0 ;
        
  
        a = s.nextInt();
        b = s.nextInt();    
        c = s.nextInt();
          
          int result = 0;
          
          System.out.println(Math.min(a-b,c+1));

  
  
    
    
    }

}