package yukicoder;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class N275 {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		ArrayList<Integer> hoge = new ArrayList<Integer>();
		int n = sc.nextInt();
		for(int i = 0; i < n; ++i){
			hoge.add(sc.nextInt());
		}
		Collections.sort(hoge);
		if(n % 2 == 1){
			System.out.println(hoge.get(n / 2));
		}else{
			System.out.println((double) (hoge.get(n / 2) + hoge.get(n / 2 - 1)) / 2);
		}
	}
}