How many parties in how many cities did hotel heiress Paris Hilton have to celebrate her 21st birthday?

• two parties in two cities
  Paris Hilton had six birthday parties in five cities around the world. That's what everyone does when they turn 21, right?
• four parties in three cities
  Paris Hilton had six birthday parties in five cities around the world. That's what everyone does when they turn 21, right?
• six parties in five cities
  Paris Hilton had six birthday parties in five cities around the world. That's what everyone does when they turn 21, right?