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.*;
import java.lang.*;

public class Rextester{
    public static void main(String[] args)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        //int n = new Integer(br.readLine());
        StringTokenizer st = new StringTokenizer(br.readLine());
        br.close();
        int n = new Integer(st.nextToken());
        int a = new Integer(st.nextToken());
        int b = new Integer(st.nextToken());
        if(a+1>=n-b){
            System.out.println(n-a);
        }
        else{
            System.out.println(b+1);
        }
    }
}