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