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.IOException;
import java.io.InputStreamReader;


public class TheNumberOfPositions {

	public static void main(String[] args)  throws IOException  {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String str=br.readLine();
		String strArr[]=str.split(" ");
		int pos=Integer.parseInt(strArr[0]);
		int front=Integer.parseInt(strArr[1]);
		int behind=Integer.parseInt(strArr[2]);
		if(front+behind>=pos){
			
			System.out.println(pos-front);
		}else{
			System.out.println(behind+1);
		}
		
	}

}
