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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class Main {

    public static void main(String[] args)  throws IOException {
       // System.out.println("Hello World!");


		PrintWriter out = new PrintWriter(System.out);
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter printWriter = new PrintWriter(System.out);

		String [] numbers = in.readLine().split(" ");
		int n = Integer.parseInt(numbers[0]);
		int a = Integer.parseInt(numbers[1]);
		int b = Integer.parseInt(numbers[2]);


		int left = Math.max(a, n-b-1);
		int result = n - left;


		System.out.println(result);



	}
}
