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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
 
public class Main{
    public static void main(String[] arg)throws IOException{
		BufferedReader br =new BufferedReader(new InputStreamReader(System.in));
		String str = br.readLine();
		String strARY[] = str.split(" ");
		int a = Integer.parseInt(strARY[0]);
		int b = Integer.parseInt(strARY[1]);
		
		double m = 3.305785;
		
		System.out.println((double)a*b/m);
    }
}