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.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
        //1: Declare/Define variables
        InputStreamReader reader = new InputStreamReader(System.in);
        BufferedReader in = new BufferedReader(reader);
        StringTokenizer st = new StringTokenizer(in.readLine());
        byte n = Byte.parseByte(st.nextToken()),
                a = Byte.parseByte(st.nextToken()),
                b = Byte.parseByte(st.nextToken()),
                answer = (byte) (n - a),
                extraSpace = (byte) (answer - b);

        //2: Check if the space between a and b is more than 1
        if (1 < extraSpace) {
            answer = (byte) (b + 1);
        }

        //3: Print the result
        System.out.println(answer);
    }
}
