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.io.*;

public class Empty{
	public static void main(String[] args) throws Exception{
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		int a = in.nextInt();
		int b = in.nextInt();
		int count = 0;
		if (a == b || a > b) {
			if ((n - a) > b) {
				count = b + 1;
			}
			else {
				count = (n - a);	
			}
			
		}
		
		else if (b > a && (a + b) < n) {//22 4 8
			count = b + 1;
		}
		else{//22 15 16
			count = (n - a);
		}
		
		System.out.println(count);




		



		


		 
	}
}