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:
// 2014/05/30 Tazoe

#include <iostream>
using namespace std;

int main()
{
	int a, b;
	cin >> a >> b;

	double S = (double)(a*b)/3.305785;

	cout.precision(6);
	cout << fixed << S << endl;

	return 0;
}