Janice's office is on the third floor, and she has to walk up 3 flights of stairs to get to her office.  In a single day, she goes up the three flights of stairs 5 times, down the the three flights of stairs 3 times, and uses the elevator the remainder of the time.  How many flights of stairs does Janice walk (up and down) in a single day?
Please reason step by step, and put your final answer within \boxed{}.
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