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.*;
import java.math.*;

public class codeforces
{
	  public static void main(String[] args)throws IOException
	  {
	  	   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


           Scanner sc = new Scanner(System.in);
           int n = sc.nextInt();
           int a = sc.nextInt();
           int b = sc.nextInt();

           int k = n - Math.max(a+1,n-b) + 1;
           System.out.println(k);







          
    	}

	  
}