#include <bits/stdc++.h>
using namespace std;
const long long LINF = 1e18L + 1;
const int INF = 1e9 + 1;
int main() {
  int n;
  cin >> n;
  priority_queue<double, vector<double>, greater<int> > pq;
  for (int i = 0; i < (n); ++i) {
    int v;
    cin >> v;
    pq.push(v);
  }
  long long ans = 0;
  while (pq.size() > 1) {
    int a = pq.top();
    pq.pop();
    int b = pq.top();
    pq.pop();
    pq.push((a + b) / (double)2.0);
  }
  ans = pq.top();
  printf("%lld\n", ans);
  return 0;
}
