#include <bits/stdc++.h>
using namespace std;
long long dx[4] = {0, 0, 1, -1};
long long dy[4] = {1, -1, 0, 0};
void fast() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout << setprecision(12) << fixed;
}
void solve() {
  long long n;
  cin >> n;
  vector<pair<long long, long long> > v;
  for (long long i = 0; i < n; i++) {
    long long x;
    cin >> x;
    long long y = 0, w = x;
    while (w % 2 == 0) {
      w /= 2;
      y++;
    }
    v.push_back({y, x});
  }
  sort(v.rbegin(), v.rend());
  double ans = (double)(v[0].second + v[1].second) / 2;
  for (long long i = 2; i < n; i++) {
    ans = (double)(ans + v[i].second) / 2;
  }
  cout << ans;
}
int main() {
  fast();
  long long t = 1;
  while (t--) {
    solve();
  }
}
