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.*;
import java.util.*;

public class Main {
    public static void main(String args[]) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int[] c = t_int_a(br, 3);

        int n = c[0];
        int a = c[1];
        int b = c[2];

        System.out.println(n - Math.max(a, n - (b + 1)));
    }

    public static StringTokenizer t_st(BufferedReader br) throws Exception {
        return new StringTokenizer(br.readLine());
    }

    public static int[] t_int_a(BufferedReader br, int n) throws Exception {
        StringTokenizer st = t_st(br);
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = Integer.parseInt(st.nextToken());
        }
        return a;
    }
}
