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 positions
{
	public static void main(String args[]) throws Exception
	{
		BufferedReader f=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer(f.readLine());
		int num=Integer.parseInt(st.nextToken());
		int before=Integer.parseInt(st.nextToken());
		int after=Integer.parseInt(st.nextToken());
		int temp=Math.max(before+1,num-after);
		System.out.println(num-temp+1);
	}
}