I found this on http://lenny-conundrum-answers.blogspot.com/2011/09/lenny-conundrum-round-419.html:
This sounds like a tricky question until you take it by cases. Let's look at the possibilities on drawing two Usukis:
So once you break it down you see that the only way of decreasing the number of Deluxe Usukis is to draw two at a time. In every other case you end up with a net change of 0. Given that there is an odd number of Deluxe Usukis, you can never eliminate them entirely. Assume that you keep drawing them out two by two until one is left. No matter what you do past this point you can never draw two Deluxe and therefore the number of Devilish necessarily decreases until you're out. So the last one remaining will have to be a Deluxe Usuki (whatever a Usuki is). |

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