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.Scanner;

public class Main {
	private Scanner sc;
	
	public static void main(String[] args) {
		new Main();
	}
	
	public Main() {
		sc = new Scanner(System.in);

		String[] nico = sc.nextLine().split(" ");
		int a = Integer.parseInt(nico[0]);
		int b = Integer.parseInt(nico[1]);
		
		System.out.println(a * b / 3.305785);
	}
}