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[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			String str = br.readLine();
			String[] str2 = str.split(" ");
			int[] x = new int[2];

			for (int i = 0; i < 2; i++) {
				x[i] = Integer.parseInt(str2[i]);
			}

			double ans = (x[0] * x[1]) / 3.305785;

			System.out.println(ans);

		} catch (IOException e) {
			System.out.println(e);
		}
	}

}