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 The_number_of_positions {
    
    static Scanner scanner=new Scanner(System.in);
    
    static int n,a,b,c,r;
    
    public static void main(String[] args) {
        
        n=scanner.nextInt();
        a=scanner.nextInt();
        b=scanner.nextInt();
        
        c=n-a-1;
    if(c>b){
        r=b+1;
    }else{
        r=c+1;
    }
        
        System.out.println(r);
    
    }
    
}

			  						 	  		 						  	 			