#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
  int N;
  cin >> N;
  vector<int> v(N);
  for(int i=0;i<N;i++){
    cin >> v[i];
  }
  sort(v.begin().v.end());
  double ans=v[0];
  for(int i=0;i<N-1;i++){
    ans+=(double)(ans+v[i+1])/(double)2;
  }
  cout << ans << endl;
}