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.Scanner;


public class Cf
{
  public static void main( String[] args)
  {
    Scanner scan = new Scanner (System.in);
    
    int n, a, b, s�ra, count;
    n = scan.nextInt();
    a = scan.nextInt();
    b = scan.nextInt();
    count = 0;
    
    for (s�ra = n; s�ra > a; s�ra--)
    {
    count++;
    if(count > b)
      s�ra = 0;
    
    }
    System.out.print(count);
  }
  
}



