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 static java.util.Arrays.*;

import java.util.Scanner;

public class Main {

	static void tr(Object... os) {
		System.err.println(deepToString(os));
	}

	Scanner sc = new Scanner(System.in);
	void run() {
		int a = sc.nextInt();
		int b = sc.nextInt();
		System.out.printf("%.8f\n", a * b / 3.305785);
	}

	public static void main(String[] args) throws Exception {
		new Main().run();
	}
}