传送门： Gym - 100729C
Mr. K. I. has a very big movie collection. He has organized his collection in a big stack.
Whenever he wants to watch one of the movies, he locates the movie in this stack and removes
it carefully, ensuring that the stack doesn’t fall over. After he finishes watching the movie, he
places it at the top of the stack.
Since the stack of movies is so big, he needs to keep track of the position of each movie.
It is sufficient to know for each movie how many movies are placed above it, since, with this
information, its position in the stack can be calculated. Each movie is identified by a number
printed on the movie box.
Your task is to implement a program which will keep track of the position of each movie.
In particular, each time Mr. K. I. removes a movie box from the stack, your program should
print the number of movies that were placed above it before it was removed.