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.
//124A
import java.util.Scanner;

public class Positions
{
  public static int numPositions(int people , int front , int back)
  {
    if( (front + back) == people)
      return back;
    else if((front+back) >= people)
      return people - front;
    else
      return back + 1;
  }

  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    int people = sc.nextInt();
    int front = sc.nextInt();
    int back = sc.nextInt();
    System.out.println(numPositions(people , front , back));
  }
}
