#include <bits/stdc++.h>
using namespace std;
int V[60];
int main(void) {
  int N;
  cin >> N;
  for (int i = 0; i < N; ++i) {
    cin >> V[i];
  }
  for (int i = 0; i < N - 1; ++i) {
    sort(V, V + N);
    V[i + 1] = (V[i] + V[i + 1]) / 2;
    V[i] = -1;
  }
  cout << V[N - 1] << endl;
  return 0;
}
