B"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, xe2 x80 x89y) in the 2D plane such that x and y are integers and 0 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89x, xe2 x80 x89y. There is a tree in such a point, and it has x xe2 x80 x89+ xe2 x80 x89y bananas. There are no trees nor bananas in other points. Now, Okabe draws a line with equation . Okabe can select a single rectangle with axis aligned sides with all points on or under the line and cut all the trees in all points that are inside or on the border of this rectangle and take their bananas. Okabe's rectangle can be degenerate; that is, it can be a line segment or even a point. Help Okabe and find the maximum number of bananas he can get if he chooses the rectangle wisely. Okabe is sure that the answer does not exceed 1018. You can trust him. The first line of input contains two space-separated integers m and b (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89m xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891000, 1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89b xe2 x80 x89 xe2 x89 xa4 xe2 x80 x8910000). 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. "...