#include <bits/stdc++.h>
using namespace std;
int main() {
  int n = 0;
  double average;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    cout << v[i] << endl;
  }
  if (n > 2) {
    sort(v.begin(), v.end());
    average = (v[0] + v[1]) / 2.0;
    for (int j = 2; j < n; j++) {
      average = (average + v[j]) / 2.0;
    }
  } else {
    average = (v[0] + v[1]) / 2.0;
  }
  cout << average << endl;
  return 0;
}
