import java.io.File;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {
        Scanner s = new Scanner(System.in);

        int n = s.nextInt();

        int[] arr = new int[n];

        for (int i = 0; i < n; i++) {
            arr[i] = s.nextInt();
        }

        Arrays.sort(arr);

        int midLow = (n / 2) - 1;


        int low = arr[midLow] + 1;
        int high = arr[midLow + 1];

        System.out.println(high - low + 1);
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz