#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

int main() {
  int n;
  cin >> n;
  vector<double> v(n);
  for (auto& a : v) {
    cin >> a;
  }
  sort(v.begin(), v.end());
  if (n % 2) {
    cout << v[n/2] << endl;
  } else {
    cout << (v[n/2-1] + v[n/2]) / 2 << endl;
  }
}