Two Bums Are Sharing A Drink...

A little background - in Russia it's kind of a cultural thing to drink in groups of three

Two bums are sitting in an alley behind a liquor store and sharing a bottle of cheap vodka when a third bum comes up to them.

• "Hey guys, can I be the third?"
  
• "No, but you can be the fourth!"
  
• "What?"
• "We already told three others to go fuck themselves"