import java.util.Scanner;

public class Charity {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int DaysForCharity = Integer.parseInt(scanner.nextLine());
        int PastryChefs = Integer.parseInt(scanner.nextLine());
        int Cakes = Integer.parseInt(scanner.nextLine());
        int Waffles = Integer.parseInt(scanner.nextLine());
        int Pancakes = Integer.parseInt(scanner.nextLine());
        int CakeProfit = Cakes * 45 ;
        double WafflesProfit = Waffles * 5.80;
        double PancakesProfit = Pancakes * 3.20;
        double ProfitPerDay = (CakeProfit + WafflesProfit + PancakesProfit)* PastryChefs;
        double CampaingSum = ProfitPerDay * DaysForCharity ;
        double FinalProfit = CampaingSum - 1.0/8 * CampaingSum;
        System.out.printf("%.2f", FinalProfit);
    }
}