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;
import java.util.StringTokenizer;

public class NoOf {
	public static void main(String[] args) throws IOException {
		BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer(bf.readLine());
		int n=Integer.parseInt(st.nextToken());
		int a=Integer.parseInt(st.nextToken());
		int b=Integer.parseInt(st.nextToken());
		if(n==1 || n==0)
			System.out.println(n);
		else if(b+a<n){//chekc this example 9 4 3
			System.out.println(b+1);
			
		}
		else{
			System.out.println(n-a);
		}
		
			

	}

}
