#include <bits/stdc++.h>
using namespace std;
template <typename T>
void deb(T v[], long long n) {
  if (false) cerr << "ARRAY   : ";
  long long i;
  for (i = 0; i < n; i++)
    if (false) cerr << v[i] << " ";
  if (false) cerr << endl;
}
template <typename T>
void deb(set<T> s) {
  if (false) cerr << "SET     : ";
  for (auto it : s)
    if (false) cerr << it << " ";
  if (false) cerr << endl;
}
template <typename T>
void deb(vector<T> v) {
  if (false) cerr << "VECTOR : ";
  long long i;
  for (i = 0; i < v.size(); i++)
    if (false) cerr << v[i] << " ";
  if (false) cerr << endl;
}
template <typename T>
void deb(stack<T> s) {
  if (false) cerr << "STACK   : ";
  stack<T> st = s;
  while (st.size()) {
    if (false) cerr << st.top() << " ";
    st.pop();
  };
  if (false) cerr << endl;
}
template <typename T>
void deb(queue<T> q) {
  if (false) cerr << "Queue   : ";
  queue<T> qq = q;
  while (qq.size()) {
    if (false) cerr << qq.front() << " ";
    qq.pop();
  };
  if (false) cerr << endl;
}
void deb(map<long long, long long> m) {
  if (false) cerr << "MAP : ";
  for (auto it : m)
    if (false) cerr << it.first << " : " << it.second << endl;
}
void deb(unordered_map<long long, long long> m) {
  if (false) cerr << "MAP : ";
  for (auto it : m)
    if (false) cerr << it.first << " : " << it.second << endl;
}
template <typename T>
T abs(T a) {
  return a < 0 ? a * -1 : a;
}
void swap(long long &x, long long &y);
bool isPrime(long long n);
long long power(long long x, long long y, long long p);
long long gcdExtended(long long a, long long b, long long *x, long long *y);
long long modInverse(long long b, long long m);
long long modDivide(long long a, long long b, long long m);
void simpleSieve(long long N, bool[]);
void PrimeDivisorSieve(long long N, long long prime[]);
class nCrModPClass {
 public:
  vector<long long> f, fi;
  long long N;
  long long MOD;
  long long poww(long long a, long long b, long long m) {
    long long ans = 1;
    while (b) {
      if (b & 1) ans = (ans * a) % m;
      b /= 2;
      a = (a * a) % m;
    }
    return ans;
  }
  long long modinvv(long long k) { return poww(k, MOD - 2, MOD); }
  nCrModPClass(long long size, long long mod) {
    MOD = mod;
    N = size + 10;
    f.resize(N);
    fi.resize(N);
    f[0] = f[1] = 1;
    for (long long i = 2; i < N; i++) f[i] = (f[i - 1] * i) % MOD;
    fi[N - 1] = modinvv(f[N - 1]);
    for (long long i = N - 2; i >= 0; i--) fi[i] = (fi[i + 1] * (i + 1)) % MOD;
  }
  long long nCrModPfromClass(long long n, long long r) {
    if (r > n) return 0;
    long long ret = f[n];
    ret %= MOD;
    ret *= fi[r];
    ret %= MOD;
    ret *= fi[n - r];
    ret %= MOD;
    return ret;
  }
};
long long testCases;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  testCases = 1;
  while (testCases--) {
    long long n;
    cin >> n;
    long long arr[n];
    long long i, j;
    for (i = 0; i < n; i++) cin >> arr[i];
    long long mul = log2(n) / 2 + 1;
    long long ans = 0;
    sort(arr, arr + n);
    long long ind = n - 1;
    long long ct = 0;
    long long curLen = 0;
    long long rem = 1;
    while (ind >= 0) {
      ans += arr[ind] * mul;
      if (pow(4, curLen) == n - ind) {
        if (false) cerr << ("ind") << " is : " << (ind) << endl;
        curLen++;
        mul--;
      }
      ind--;
    }
    cout << ans << endl;
  }
  return 0;
}
void simpleSieve(long long N, bool prime[]) {
  long long i, j;
  for (i = 0; i < N + 1; i++) prime[i] = true;
  for (i = 2; i * i <= N; i++) {
    if (prime[i]) {
      for (j = i * i; j <= N; j += i) {
        prime[j] = false;
      }
    }
  }
}
void PrimeDivisorSieve(long long N, long long prime[]) {
  long long i, j;
  for (i = 0; i < N + 1; i++) prime[i] = i;
  for (i = 2; i * i <= N; i++) {
    if (prime[i] == i) {
      for (j = i; j <= N; j += i) {
        if (prime[j] == j) prime[j] = i;
      }
    }
  }
}
void swap(long long &x, long long &y) {
  x ^= y;
  y ^= x;
  x ^= y;
}
bool isPrime(long long n) {
  if (n <= 1) return false;
  for (long long i = 2; i < n; i++)
    if (n % i == 0) return false;
  return true;
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long gcdExtended(long long a, long long b, long long *x, long long *y) {
  if (a == 0) {
    *x = 0, *y = 1;
    return b;
  }
  long long x1, y1;
  long long gcd = gcdExtended(b % a, a, &x1, &y1);
  *x = y1 - (b / a) * x1;
  *y = x1;
  return gcd;
}
long long modInverse(long long b, long long m) {
  long long x, y;
  long long g = gcdExtended(b, m, &x, &y);
  if (g != 1) return -1;
  return (x % m + m) % m;
}
long long modDivide(long long a, long long b, long long m) {
  a = a % m;
  long long inv = modInverse(b, m);
  if (inv == -1)
    return -1;
  else
    return (inv * a) % m;
}
