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

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            double over20 = double.Parse(Console.ReadLine());
            double kg = double.Parse(Console.ReadLine());
            int days = int.Parse(Console.ReadLine());
            int lug = int.Parse(Console.ReadLine());
            double lugPr = 0;
            double total = lugPr * lug;
            double price = 0;
            if (kg > 20 && days >30)
            {
                lugPr = over20;
                price = total + total * 0.10;
            }
            else if (kg >= 10 && kg <= 20 && days >=7 && days <=30)
            {
                lugPr = over20 * 0.5;
                price = total + total * 0.15;
            }
            else if (kg < 10 && days<7)
            {
                lugPr = over20 * 0.2;
                price = total + total * 0.40;
            }
            Console.WriteLine($"The total price of bags is: {price} lv.");
        }
    }
}