Problem: 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

Solution (in JAVA):

Solution:
import java.util.Scanner;

public class Main
{
  static final double TSUBO = 3.305785;

  public static void main(String[] args)
  {
    try (Scanner scanner = new Scanner(System.in);)
    {
      while (scanner.hasNextLine())
      {
        String[] strArray = scanner.nextLine().split(" ");
        double a = Double.valueOf(strArray[0]);
        double b = Double.valueOf(strArray[1]);
        solver(a, b);
      }
    }
  }

  private static void solver(double a, double b)
  {
    System.out.printf("%.6f\n" ,(a * b) / TSUBO);
  }
}