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 JavaApplication2 {

 
 
    public static void main(String[] args) {
        int a,b,n,pos,cant;
        
        Scanner sc = new Scanner(System.in);
        
        n = sc.nextInt();
        a = sc.nextInt();
        b = sc.nextInt();
        
        pos = 1;
        cant = 0;
       
        while(pos<=n){
            if(pos-1 >= a && n-pos<=b)
            {
               
                cant = cant+1;
            }
            pos=pos+1;
        }
            
        System.out.print(cant);
        System.out.println();
    }
    
}

