Have you ever heard of the unit "○○ tsubo" that expresses the area of ​​land? Since ancient times, one samurai has said the area for making rice to eat in a day.

There is a land of a [m] x b [m]. Enter a and b and create a program that outputs the tsubo area S [tsubo] of the land. 1 tsubo = 3.305785 [m2], and a and b are integers less than or equal to 100.



input


a b


A and b separated by one space are given on one line.

output

Output the tsubo area S in one line. An error of 0.0001 or less is allowed.

Example

Input

15 25


Output

113.437508
import java.util.*;
import java.text.*;
/*
Main class for AOJ where there is no input.
*/
public class Main{
   static final double T = 3.305785;
   public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    String[] arr = sc.nextLine().split(" ");
    double a = Double.parseDouble(arr[0]);
    double b = Double.parseDouble(arr[1]);
    
    System.out.println(a*b/T);
    
   }//main
}//class