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.*;
public class Main
{
	public static void main(String[] args) 
	{
		Scanner in=new Scanner(System.in);
		while(in.hasNext())
		{
			int a=in.nextInt();
			int b=in.nextInt();
			System.out.println(a*b/3.305785);
		}
	}
	
	static public void debug(Object... o)
	{
		System.err.println(Arrays.deepToString(o));
	}
}