#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
#include<string>
#include<sstream>
#include<cctype>
#include<functional>
#include<iomanip>
using namespace std;

int main()
{
	int n;
	double a;
	vector<double>v;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> a;
		v.push_back(a);
	}
	sort(v.begin(), v.end());
	if (n % 2 == 0)
	{
		cout << (v[n / 2] + v[n / 2 - 1]) / 2.0 << endl;
	}
	else
	{
		cout << v[n / 2] << endl;
	}
	return 0;
}