#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
int main() {
	int N, i;
	cin >> N;
	vector<double> A(N);
	for (i = 0; i < N; i++) { cin >> A[i]; }
	sort(A.begin(), A.end());
	if (N % 2 == 1) cout << A[N / 2];
	if (N % 2 == 0) cout << (A[N / 2] + A[N / 2 - 1]) / 2;
	return 0;
}