#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
	vector<int> arr;
	int a;
	float b;
	cin >> a;
	arr.resize(a);
	while (a > 0)
	{
		cin >> arr[a-1];
		a--;
	}

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

	if (arr.size() % 2 == 1)
	{
		b = (float)(arr[arr.size() / 2]);
	}

	else
	{
		b = (float)((arr[arr.size() / 2] + arr[(arr.size() / 2) - 1]) / 2);
	}

	cout << b << endl;
	return 0;
}