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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {

		InputStreamReader is = new InputStreamReader(System.in);
		BufferedReader br = new BufferedReader(is);

		String str;
		if((str=br.readLine())!=null){
			String[] sp = str.split(" ");

			double tubo = 3.305785;
			double a = Double.parseDouble(sp[0]);
			double b = Double.parseDouble(sp[1]);

			System.out.println(a * b / tubo);


		}
	}
}