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.io.*;
import java.util.*;

public class NumberPosition{
	public static void main(String args[])throws IOException{
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String s[] = in.readLine().split(" ");
		int n = Integer.parseInt(s[0]);
		int f = Integer.parseInt(s[1]);
		int b = Integer.parseInt(s[2]);
		int x = n-f-1;
		int res = 0;
		if(x>b){
			res = b+1;
		}else{
			res=x+1;
		}
		System.out.println(res);
	}
}