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.*;
/**
 *
 * @author Aaryan
 * AV 
 */
public class Test {
    public static void main(String[] args) throws Exception {
         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
       String str1 [] = br.readLine().split(" ");
       
       int n = Integer.parseInt(str1[0]);
       int a = Integer.parseInt(str1[1]);
        int b = Integer.parseInt(str1[2]);
       int res =Math.min(n-a,b+1);
                out.println(res );
                out.flush();
            }   
    }
