#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int n; 
    scanf("%d",&n);
    int *calories = malloc(sizeof(int) * n);
    for(int calories_i = 0; calories_i < n; calories_i++){
       scanf("%d",&calories[calories_i]);
    }
    int f=1;
    // your code goes here
    for(int i=0;i<(n-1)&&f;i++)
    {
        f=0;
        for(int j=0;j<(n-i-1);j++)
        {
            if(calories[i]<calories[i+1])
            {
                f=1;
                calories[i]=calories[i]+calories[i+1];
                calories[i+1]=calories[i]-calories[i+1];
                calories[i]=calories[i]-calories[i+1];
            }
        }
    }
    int miles=0;
    for(int i=0;i<n;i++)
    {
        miles=miles + calories[i]*pow(2,i);
    }
    printf("%d",miles);
    return 0;
}