#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <iomanip>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(int i = 0;i < n;++i)
int main() {
	int n;
	cin >> n;
	vector<double> hoge;
	REP(i, n) {
		double a;
		cin >> a;
		hoge.push_back(a);
	}
	sort(begin(hoge), end(hoge));
	if (n % 2 == 1) {
		cout << hoge[n / 2] << endl;
	}
	else {
		cout << (hoge[n / 2] + hoge[n / 2 - 1]) / 2 << endl;
	}
}