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 CPP):

Solution:
#include <iostream>

#define TSUBO 3.305785

int main()
{
	long double a, b;
	std::cin >> a >> b;
	
	std::cout << std::fixed << a*b / TSUBO << std::endl;
	
	return 0;
}