import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] calories = new int[n];
        for(int calories_i=0; calories_i < n; calories_i++){
            calories[calories_i] = in.nextInt();
        }
        // your code goes here
        long sum=0;
        for(int i=0;i<n-1;i++){
            int key=calories[i+1];
            for(int j=i;j>=0;j--){
                if(calories[i+1]<calories[j]){
                    calories[j+1]=calories[j];
                }
                else{
                    calories[j+1]=key;
                    break;
                }
            }
            
        }
        for(int i=n-1;i>=0;i--){
            sum=(long)(sum+(Math.pow(2,i))*calories[n-1-i]);
        }
        System.out.println(sum);
    }
}