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;
import java.io.PrintWriter;

public class p124A{
	public static void main(String []args)
	{
		Scanner in = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
			int n = in.nextInt(), a = in.nextInt(), b = in.nextInt();
			// from editorial
			int pos = n - Math.max(a+1,n-b)+1;
			out.println(pos);
		out.flush();
	}
}