#include <bits/stdc++.h>
using namespace std;

int main() {
  int N;
  cin >> N;
  vector<int> A(N);
  for (int i = 0; i < N; i++) cin >> A.at(i);
  sort(A.begin(), A.end());
  cout << ((N % 2) ? A.at(N / 2) : double((A.at(N / 2 - 1) + A.at(N / 2)) / 2.0)) << "\n";
}