Full of Flies

Three men walk into a bar and the barman says, ”If you can sit in my basement for a day I’ll give you free beer forever.” So the first man says, ”Easy. I can do that.” But he walks out after five minutes and says, ”It’s impossible, you got a swarm of flies in there.”
So the second man tries his luck, but can’t take more than 10 minutes.
Finally the third man goes in and comes out a day later. The others ask him how he did it. He said, “Easy. I took a dump in one corner and sat in the other corner!”