Misha and Geometry

Misha is an expert in geometry, so he knows a lot about various geometrical objects. Recently, he learned the definition of a convex polygon and invented too many new problems involving it. Please help him solve one such problem. You are given N queries, queries can be one of the following two types: - + x y - Add point (x, y) into multiset of points. - - x y - Erase exactly one point (x, y)