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.InputStreamReader;

public class TheNumberOfPositions_CF {
    public static void main(String[] args) {
        try {
            String line = new BufferedReader(new InputStreamReader(System.in)).readLine();
            String[] pos = line.split(" ");
            int n = Integer.parseInt(pos[0]);
            int a = Integer.parseInt(pos[1]);
            int b = Integer.parseInt(pos[2]);
            
            if(n>=0 && n<=100 && a>=0&&a<=n&& b>=0&&b<=n){
                if (a+b<n) {
                    System.out.println(b+1);
                } else {
                    System.out.println(n-a);
                }   
            }else{
                
            }   
        } catch (Exception e) {

        }
    }
}