Squares and rectangles fascinated the famous Dutch painter Piet Mondriaan.
One night, after producing the drawings in his 'toilet series' (where he had to use his toilet paper to draw on, for all of his paper was filled with squares and rectangles), he dreamt of filling a large rectangle with small rectangles of width 2 and height 1 in varying ways.
Expert as he was in this material, he saw at a glance that he'll need a
computer to calculate the number of ways to fill the large rectangle
whose dimensions were integer values, as well. Help him, so that his
dream won't turn into a nightmare!