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.util.*;
import java.io.*;
 public class Hello {

public static void main (String[]args) throws java.lang.Exception  {
	BufferedReader bf = new BufferedReader( new InputStreamReader(System.in));
	String[] ns = bf.readLine().split(" ");
	int n = Integer.parseInt(ns[0]); int m = Integer.parseInt(ns[1]);
	int o=Integer.parseInt(ns[2]);
	int x = n-m;
	while(x>o+1)
		x--;
	System.out.print(x);
 } 
}


