A great Polish joke I heard…

Being Polish, I can really appreciate this one:

A polish man finds a lantern laying on the ground.
He takes it home and while cleaning it a genie appears.
The Genie says:
“For freeing me from the lantern, I shall grant you three wishes.”
The polish man thinks for a second and says “I wish for a mongol invasion of Poland, please.”
The Genie grants him his wish, the mongols invade, and then leave.
The Genie says “Name your second wish.”
The man thinks for a moment and says “I wish for a mongol invasion of Poland, please.”
The Genie looks at bit puzzled, but grants him his wish.
The Mongol invade, and then leave.
“Now name you third wish”
The man thinks for a bit and says “I wish for a mongol invasion of Poland, please.”
The confused Genie says “I’ll grant you your wish, but would you tell me why you keep wishing for this?”
The polish man says “Sure, each time the mongols invade Poland they have to go through Russia twice.”