import java.util.*;
class Main{
    public static void check(int n, double m)
    {
        if(n<0 || n>24 || m<0 || M>10){
            System.out.print("Invalid input");
            return;
        }
        System.out.printf("%.2f",n*m);
    }
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        try{
            int n = sc.nextInt();
            double m = sc.nextDouble();
            check(n,m);
        }
        catch(Exception e)
        {
            System.out.print("Invalid input");
        }
    }
}