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 position {

	
	public static void main(String[] args) {
		Scanner l=new Scanner(System.in);
		int n,a,b;
		n=l.nextInt();
		a=l.nextInt();
		b=l.nextInt();
		n=n-a;
		if(n-b==0){
			System.out.println(b);
		}else{
			if(n-b>0){System.out.println((b+1));}
			else{
			System.out.println(n);}
		}
	}

}
