CF821B Okabe and Banana Trees

Okabe needs bananas for one of his experiments for some strange reason. So he decides to go to the forest and cut banana trees. Consider the point $ (x,y) $ in the 2D plane such that $ x $ and $ y $ are integers and $ 0

The first line of input contains two space-separated integers $ m $ and $ b $ ( $ 1

Print the maximum number of bananas Okabe can get from the trees he cuts.

The graph above corresponds to sample test 1. The optimal rectangle is shown in red and has $ 30 $ bananas.