Takahashi made N problems for competitive programming. The problems are numbered 1 to N, and the difficulty of Problem i is represented as an integer d_i (the higher, the harder).

He is dividing the problems into two categories by choosing an integer K, as follows:

* A problem with difficulty K or higher will be for ARCs.
* A problem with difficulty lower than K will be for ABCs.



How many choices of the integer K make the number of problems for ARCs and the number of problems for ABCs the same?

* 2 \leq N \leq 10^5
* N is an even number.
* 1 \leq d_i \leq 10^5
* All values in input are integers.



Input

Input is given from Standard Input in the following format:


N
d_1 d_2 ... d_N


Output

Print the number of choices of the integer K that make the number of problems for ARCs and the number of problems for ABCs the same.

Examples

Input

6
9 1 4 4 6 7


Output

2


Input

8
9 1 14 5 5 4 4 14


Output

0


Input

14
99592 10342 29105 78532 83018 11639 92015 77204 30914 21912 34519 80835 100000 1


Output

42685
import java.util.*;
import java.util.Arrays;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
      	int a[] = new int[n];
      	int s = 0;
      	for (int i = 0; i < n; i++){
          	a[i] = sc.nextInt();
        }
        Arrays.sort(a);
        s = a[n/2] - a[n/2-1];
        System.out.println(s);
    }
}