import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        Arrays.sort(arr);
        double ans;
        if (n % 2 == 0) {
            ans = (arr[n / 2 - 1] + arr[n / 2]) / 2.0;
        } else {
            ans = arr[n / 2];
        }
        System.out.println(ans);
    }
}