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.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) throws IOException{
        try (   PrintWriter printWriter = new PrintWriter(System.out);
                Scanner scanner = new Scanner(System.in)
                ){
            int n = scanner.nextInt();
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if(a >= n-(b+1)){
                printWriter.print(n-a+"\n");
            }
            else
                printWriter.print(b+1+"\n");
        }
    }
    
}