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 Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        // int T = Integer.parseInt(br.readLine());
        // while(T-- > 0){
            String[] s = br.readLine().split("\\s");
            int N = Integer.parseInt(s[0]);
            int A = Integer.parseInt(s[1]);
            int B = Integer.parseInt(s[2]);
            // String s2 = br.readLine();
            // int[] arr = new int[10];
            // s = br.readLine().split("\\s");
            // for(int i=1;i<=9;++i) arr[i] = Integer.parseInt(s[i-1]);
            // s = br.readLine().split("\\s");
            // for(int i=0;i<a;++i) y[i] = Integer.parseInt(s[i]);
            System.out.println(solve(N,A,B)); 
            //solve(N,M);
            //br.readLine();
        //}
    }
    
    private static int solve(int N,int A,int B){
        return Math.min(N - A,B + 1);
    }
}