import java.util.*;

class Parking{
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        if (!sc.hasNextInt()) {
            System.out.println("Invalid input");
            sc.close();
            return;
        }
        int hoursParked = sc.nextInt();

        if (!sc.hasNextDouble()) {
            System.out.println("Invalid input");
            sc.close();
            return;
        }
        
        if (hoursParked < 0 || hoursParked > 24) {
            System.out.println("Invalid input");
            sc.close();
            return;
        }
        
        if (hourlyRate < -10 || hourlyRate > 10) {
             System.out.println("Invalid input");
            sc.close();
            return;
        }


        double hourlyRate = sc.nextDouble();
        
        double totalFee = hoursParked * hourlyRate;

        System.out.printf("%.2f%n", totalFee);

    }
}