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 main 
{
	public static void main(String[] args) throws Exception 
	{
		Scanner in = new Scanner(System.in);
		
		int numPeople = in.nextInt();
		
		int front = numPeople - in.nextInt();
		int back = numPeople - (numPeople - (in.nextInt() + 1));
		
		if(front < back)
		{
			System.out.println(front);
		}
		else
		{
			System.out.println(back);
		}
	}
}
