#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
	int n;
	cin >> n;
	vector<int> a(n);
	for (auto &x : a) cin >> x;
	sort(a.begin(), a.end());
	cout << (n % 2 == 1 ? a[n / 2] : (a[n / 2 - 1] + a[n / 2]) / 2.0) << endl;
}