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 line {

	public static void main(String[] args) {
		int n, a, b;
		Scanner s = new Scanner(System.in);
		int count = 0;

		n = s.nextInt();
		a = s.nextInt();
		b = s.nextInt();



		if(n-a<=b)
		{
			
			count=n-a;
		}
		else
		{
			count=b+1;
		}
		
		
			
		

		System.out.println(count);

		s.close();

	}

}
