using System;

namespace FamilyTrip
{
    class Program
    {
        static void Main(string[] args)
        {

            double budget = double.Parse(Console.ReadLine());
            int nightCnt = int.Parse(Console.ReadLine());
            double nightPrice = double.Parse(Console.ReadLine());
            double percent = double.Parse(Console.ReadLine());

            if (nightCnt > 7)


            {

                double discount = nightPrice * 0.05;
                double nightCntTotal = nightCnt * (nightPrice * 0.95);
                percent = budget * 0.02;
                double totalexpences = nightCntTotal + percent;
                double moneyleft = budget - totalexpences;

                Console.WriteLine($"Ivanovi will be left with {moneyleft:f2} leva after vacation.");


            }
            else


            {

                double nightCntTotal = nightCnt * nightPrice;
                percent = budget * 0.15;
                double totalSum = nightCntTotal + percent;
                double moneyNeed = totalSum - budget;
                Console.WriteLine($"{moneyNeed:f2} leva needed.");


            }


        }
    }
}