#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, p, q, r, n, i;
  double sum = 0, t, y, k;
  cin >> n;
  int x[n];
  for (i = 0; i < n; i++) {
    cin >> x[i];
  }
  for (i = 0; i < n; i++) {
    sum = sum + x[i];
  }
  if (sum / n != x[0]) {
    t = sum * n;
    y = pow(2, n);
    k = t / y;
    cout << k << endl;
  } else
    cout << x[0] << endl;
  return 0;
}
