#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[i];
  sort(A.begin(), A.end());
  double ans = A[N / 2];
  if (N % 2 == 0)
    ans = (ans + A[N / 2 - 1]) / 2;
  cout << ans << endl;
}