#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  vector<uint16_t> v;
  cin >> N;
  v.resize(N);
  for (int i = 0; i < N; i++) cin >> v[i];
  sort(v.begin(), v.end(), less<uint16_t>());
  double value = 0;
  for (int i = 0; i < N; i++) {
    value += (value + v[i]) / 2.0;
  }
  cout << value;
}
