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 PYTHON3):

Solution:

if __name__ == '__main__':
	
	while True:
		try:
			n,m = map(int,input().split())
			if n == 0 and m == 0:
				break

			ans = n * m / 3.305785
			print('{:.5f}'.format(ans))

		except EOFError:
			break