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.*;
import java.lang.*;

public class Main{
    
    public static void main(String[] args) throws java.lang.Exception{
        
        try{
            Scanner scn = new Scanner(System.in);
            long n = scn.nextLong();
            long a = scn.nextLong();
            long b = scn.nextLong();
            
            if(n-a <=b){
                System.out.println(n-a);
            }
            else{
                System.out.println(b+1);
            }
            
        }
        catch(Exception e){
            return;
        }
    }
}