We're not on the fourth floor!

The last (fourth) flight of narrow stairs we have to negotiate to get to our apartment.

After a few days I finally decided to count the flights of stairs we were walking up.  To our surprise, there were four.  But wait, our apartment is 4A!  Oh, I forgot that in Europe they start with floor 0.  So by U.S. standards we're on the fifth floor, not the fourth.  Thank goodness we have an elevator that takes us up the first three flights and we only have to walk the fourth, when we're tired or carrying heavy items up to the apartment.