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.Arrays;

public class NumberOfPositions {
	static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
	public static void main(String [] args) throws IOException 
	{
		int [] nab = Arrays.stream(reader.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
		int n = nab[0];
		int a = nab[1];
		int b = nab[2];

		int maxB = n - a - 1;
		maxB = (maxB < b) ? maxB + 1 : b + 1;
		System.out.println(maxB);
	}
}