#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, temp=0;
    long miles=0.0; 
    scanf("%d",&n);
    int *calories = malloc(sizeof(int) * n);
    for(int calories_i = 0; calories_i < n; calories_i++){
       scanf("%d",&calories[calories_i]);
    }
    for(int calories_i = 0; calories_i < n; calories_i++)
        {
         if(calories[calories_i]<calories[calories_i+1])
             {
         temp=calories[calories_i];
         calories[calories_i]=calories[calories_i+1];
         calories[calories_i+1]=temp;
         }
                 miles+=((pow(2.0,calories_i))*calories[calories_i]);
        }
    /*for(int calories_i = 0; calories_i < n; calories_i++)
        {
         miles+=((pow(2.0,calories_i))+calories[calories_i]);
        }*/
    printf("%ld",miles);
  //return 0;
}