Question 135
Two cells of a $2 \times 64$ grid are to be colored. A subrectangle is defined as a rectangle whose sides are aligned with the grid lines and whose vertices lie on grid points. Determine which two cells should be colored so that the number of subrectangles containing at least one of the two colored cells is maximized. What is the maximum possible number of such subrectangles?
(Batbayasgalan Balkhuu)
(Batbayasgalan Balkhuu)