using System;
namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var projectParts = int.Parse(Console.ReadLine());
            var moneyAward = double.Parse(Console.ReadLine());

            double totalScore = 0.0;
            double currentAddition = 0.0;
            for (int i = 1; i <= projectParts; i++)
            {
                var scoreForCurrentPart = double.Parse(Console.ReadLine());

                if (i % 2 == 0)
                {
                    currentAddition = scoreForCurrentPart * 2;
                }
                else
                {
                    currentAddition = scoreForCurrentPart;
                }
                totalScore += currentAddition;
            }
            double award = moneyAward * totalScore;
            Console.WriteLine($"The project prize was {award:f2} lv.");
        }
    }
}