using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        //var arr = new SortedList<int,int>{{8,8},{4,4},{6,6},{12,12}};

        var arr = new SortedSet<int>(){8,4,6,12};

        var cost = 0;

        //arr.Sort();

        while(arr.Count>1){

            var sum = arr.Min;

            arr.Remove(arr.Min);

            sum = sum + arr.Min;

            arr.Remove(arr.Min);

            //Console.WriteLine(arr.Count);

            arr.Add(sum);

            cost = cost + sum;

        }

        Console.WriteLine(cost);

    }

}