using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DataTypesLab
{
    class Program
    {

        static void Main(string[] args)

        {
            int splitCount = int.Parse(Console.ReadLine());
            double prizeByPoint = double.Parse(Console.ReadLine());
            int totalPoints = 0;
            for (int i = 0; i < splitCount; i++)
            {
                int points = int.Parse(Console.ReadLine());
                if (i%2!=0)
                {
                    points *= 2;
                }
                totalPoints += points;
            }
            double prize = prizeByPoint * totalPoints;
            Console.WriteLine($"The project prize was {prize:f2} lv.");
        }


    }
}