#include <bits/stdc++.h>
using namespace std;
void solve() {
  int N;
  cin >> N;
  vector<int> V;
  for (int i = 0; i < N; i++) {
    int v;
    cin >> v;
    V.push_back(v);
  }
  sort(V.begin(), V.end());
  double ans = (V[0] + V[1]) / 2.0;
  cout << ans << endl;
  for (int i = 2; i < N; i++) {
    ans = (ans + V[i]) / 2.0;
  }
  cout << setprecision(15) << ans << endl;
}
int main() { solve(); }
