# The first integer represents the number of pages.
# Subsequent integers constitute the reference stream.
# The reference stream consists of a list of pages which 
# will be accessed in the order from left to right.

26 1 2 3 4 6 5 7 6 8 7 9 8 10 9 11 10 12 11 13 12 14 16 17 18 19 6