#include<iostream>
#include<algorithm>
#include <vector>
#include<cmath>
#include<iomanip>
using namespace std;
typedef long long int lont;
int main() {
	int N;
	cin >> N;
	vector<double>vec(N);
	for (int ia = 0; ia < N; ia++) {
		cin >> vec.at(ia);
	}
	sort(vec.begin(), vec.end());
	if (N % 2 == 0) {
		cout << ((vec.at(N / 2 - 1) + vec.at(N / 2)) / 2) << endl;
	}
	else {
		cout << vec.at(N / 2) << endl;
	}
}