#include <bits/stdc++.h>
using namespace std;

int main() {
	int N;
	cin >> N;

	vector<int> v(N);
	for (int i = 0; i < N; i++) {
		cin >> v.at(i);
	}

	sort(v.begin(), v.end());
	double a = 0;
	if (!(N % 2)) {
		a = v.at(N / 2 - 1) + v.at(N / 2);
		a /= 2.0;
	}
	else {
		a = v.at(N / 2);
	}

	cout << fixed << setprecision(1) << a << endl;
}