package no275;

import java.util.Arrays;
import java.util.Scanner;

public class Main {

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

}