#include <bits/stdc++.h>

using namespace std;

int main(){
    int n;
    cin >> n;
    vector<int> calories(n);
    for(int calories_i = 0; calories_i < n; calories_i++){
       cin >> calories[calories_i];
    }
    // your code goes here
    long long walk = 0;
    int i, j;
    long max;
    int index;
    long long square = 1;
    for (i = 0; i < n; i++) {
        max = -1;
        for (j = 0; j < n; j++) {
            if (calories[j] > max) {
                max = calories[j];
                index = j;
            }
        }
        if (max > -1) {
            walk += max * square;
            calories[index] = -1;
        }
        square *= 2;
    }
    cout << walk << endl;
    return 0;
}