As a director of cities transportation construction, Elfness is given a mission to connect n cities by
a lot of roads. Of course, the more roads to be built, the more convenient it would be. But if there
are two roads cross each other, traffic accidents may happen. So it means on Elfness’s ACM(All
Cities’ Map), there are no cross roads. And now, Elfness wants to know how many roads can be
built at most(Attention: a road won’t have to be a segment, it can be a straight line or a ray)?