#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[51] = {0};
  cin >> n;
  double m = n - 1;
  double p = pow((double)2, m);
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  int sum = a[0];
  for (int j = n - 1; j > 0; j--) {
    p = p / 2;
    int r = a[j] * p;
    sum += r;
  }
  int ans = sum / pow((double)2, m);
  cout << ans << '\n';
  return 0;
}
