using System;
using System.Linq;
using System.Collections.Generic;

namespace ZadachiTest
{
    class Program
    {
        static void Main(string[] args)
        {
            int pizzaCount = int.Parse(Console.ReadLine());
            double[] priceSave = new double[pizzaCount];
            string pizzaPrice = Console.ReadLine();
            string[] values = pizzaPrice.Split(' ');
            double total = 0;
            double temp;
            int count = pizzaCount - 1 ;
            for (int i = 0; i < pizzaCount; i++)
            {
                priceSave[i] = double.Parse(values[i]);
            }

            Array.Sort(priceSave);
            while (pizzaCount != 0)
            {
                if (pizzaCount >= 3)
                {
                    total += priceSave[count] + priceSave[count - 1] + 5;                   
                    pizzaCount -= 3;
                }
                else if (pizzaCount >= 2)
                {
                    temp = priceSave[count - 1] * 0.6;
                    total += priceSave[count] + temp;
                    pizzaCount -= 2;
                }
                else if (pizzaCount == 1)
                {
                    total += priceSave[count];
                }
            }
            Console.WriteLine(total);
        }
    }
}