Inspired by http://xkcd.com/1331/
In this xkcd comic, there are several gifs that all blink with different frequency. I want to know what the period would be if was all a single GIF. Given a list of numbers representing the individual frequencies, output the period of the overall GIF.
N f1 f2 . . . fN
Where N is the number of frequencies, fi is the ith frequency, and P is the resulting period of the total GIF.
You may choose to use any delimiting character you want(instead of \n), and you may exclude the N if you wish, and it will be inferred by the number of delimeters.
Frequencies are the closest double-precision floating point representation of the numbers provided as input.
The outputted period is a 64-bit unsigned integer, rounded(up on 0.5) to the nearest whole. Any input that would produce a period bigger than 2^64-1 is considered undefined behaviour.
Likewise any input <= 0 is considered undefined behaviour.
Code golf so shortest code wins!