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.Scanner;


public class Main{
    
    public static void main(String[] args){
        String line;
        Scanner sc= new Scanner(System.in);
        while(sc.hasNextLine()){
            String[] a= sc.nextLine().split(" ");
            int dif=Integer.parseInt(a[0]) - (Integer.parseInt(a[1])+Integer.parseInt(a[2]));
            if(dif<2){
            System.out.println(Integer.parseInt(a[0])-Integer.parseInt(a[1])); }
            else{
                System.out.println(Integer.parseInt(a[0])-Integer.parseInt(a[1])-(dif-1));
            }
            }
            
        }       
        
        
    }   