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.*;
import java.io.*;

public class Main {
	public void solve() throws IOException {
		int a = nextInt();
		int b = nextInt();
		double x = 3.305785;
		writer.println(a*b/x);
	}

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

	BufferedReader reader;
	StringTokenizer tokenizer;
	PrintWriter writer;

	public void run() throws IOException {
		try {
			reader = new BufferedReader(new InputStreamReader(System.in));
			tokenizer = null;
			writer = new PrintWriter(System.out);
			solve();
			reader.close();
			writer.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public String nextToken() throws IOException {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			tokenizer = new StringTokenizer(reader.readLine());
		}
		return tokenizer.nextToken();
	}

	public int nextInt() throws IOException {
		return Integer.parseInt(nextToken());
	}
}