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;

class Main{
    public static void main(String args[]) throws IOException{
        BufferedReader bfr=new BufferedReader(new InputStreamReader(System.in));
        String str=bfr.readLine();
        String[] matome=str.split(" ");

        double a=Double.parseDouble(matome[0]);
        double b=Double.parseDouble(matome[1]);

        System.out.println(a*b/3.305785);
    }
}