Lol, you do know that 100GHs will earn you approximately $0.57 per day, right? You'd be very lucky to actually get half that after maintenance fees.

So why bother? You could probably find a 25 cents every day by looking down while going for a short walk. Plus you'll get fresh air and exercise. And it costs you nothing!

Anyways, here's the answer to your question...
∞