说明：  给定一系列2维平面点的坐标(x, y)，其中x和y均为整数，要求用一个最小的长方形框将所有点框在内。长方形框的边分别平行于x和y坐标轴，点落在边上也算是被框在内。
(Given a series of 2-dimensional plane the coordinates of points (x, y), in which x and y are integers, with a minimum requirement of a rectangular box including all the points box. Rectangular box parallel to the edge, respectively, x and y coordinate axis, point fall on the edge of the box is also regarded as being included.)