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.PrintWriter;
import java.util.Scanner;


public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		int n = sc.nextInt();
		int min = sc.nextInt();
		int max = sc.nextInt();
		sc.close();
		int count = 0;
		int t = n - max;
		if(t <= min) for(; t < (min + 1); t++);
		for(; t <= n; count++, ++t);
		out.print(count);
		out.close();
	}
	
}
