#include <algorithm>
#include <iostream>

using namespace std;

int main(int argc, const char *argv[])
{
	int N;
	cin >> N;
	int As[N];
	for (auto &&a : As) cin >> a;
	sort(As, &As[N]);
	double ret;
	if (N % 2 == 0) {
		ret = ((double)As[N / 2 - 1] + As[N / 2]) / 2;
	}
	else {
		ret = As[N / 2];
	}
	cout << ret << endl;
	return 0;
}