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 PYTHON):

Solution:
#!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin, exit


def main(readline=stdin.readline):
    a, b = (float(s) for s in readline().split())
    print('{:.6f}'.format(a * b / 3.305785))
    exit()


main()