#include <bits/stdc++.h>
#define speed                                                                  \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define oprecision                                                             \
  cout.precision(30);                                                          \
  cerr.precision(7);
#define bb bool
#define ii int
#define ll long long
#define ff float
#define dd double
#define cc char
#define ss string
#define forn(sz) for (int i = 1; i <= sz; i++)
#define forni(i, sz) for (int i = 1; i <= sz; i++)
#define fornid(i, m, sz) for (int i = m; i <= sz; i++)
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define vii vector<ii>
#define vii64 vector<ll>
#define vb vector<bb>
using namespace std;
ff sz, arr[10005], ans;
ii main() {
  speed;
  oprecision;
  /*#ifndef ONLINE_JUDGE
    freopen("outd.txt", "rt", stdin);
  #endif*/
  // code
  cin >> sz;
  forn(sz)cin >> arr[i];
  sort(arr + 1, arr + sz + 1);
  ans = (arr[1] + arr[2]) / 2;
  for(int i = 3; i <= sz; i++){
    ans = (ans + arr[i]) / 2;
  }
  cout << ans;
// endl
#ifndef ONLINE_JUDGE
  cerr << "\nTime elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
  return 0;
}