#include <bits/stdc++.h>

using namespace std;

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int n, t;
	vector <int> v;

	cin >> n;

	for (int i = 0; i < n; i++)
	{
		cin >> t;
		v.push_back(t);
	}

	sort(v.begin(), v.end());

	if (n % 2 == 1)
	{
		cout << v[n / 2] << '\n';
	}
	else
	{
		int sum = v[(n / 2) - 1] + v[(n / 2)];
		double res = (sum / 2.0);
		cout << fixed;
		cout.precision(2);

		cout << res << '\n';
	}
	return 0;
}