import java.util.Scanner;
public class ChangeTiles {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        double money=Double.parseDouble(scanner.nextLine());
        double width=Double.parseDouble(scanner.nextLine());
        double lenght=Double.parseDouble(scanner.nextLine());
        double a=Double.parseDouble(scanner.nextLine());
        double h=Double.parseDouble(scanner.nextLine());
        double piecePrice=Double.parseDouble(scanner.nextLine());
        double worker=Double.parseDouble(scanner.nextLine());
        double area=width*lenght;
        double pieceArea=(a*h)/2;
        double needPieces=Math.ceil(area/pieceArea)+5;
        double sum=needPieces*piecePrice+worker;
        if(money>=sum){double left=money-sum;
            System.out.printf("%.2f",left);
            System.out.print(" lv left.");}
        else if(money<sum){double raz=sum-money;
            System.out.print("You'll need ");
            System.out.printf("%.2f",raz);
            System.out.print(" lv more.");}


    }
}