<image>(12 points) (1) As shown in the figures ①, ②, ③, and ④, there are four plane graphs. Count each one, how many vertices does each plane graph have? How many edges? Into how many regions do they divide the plane? Please fill in the results in the table below:


(2) Observe the table above, deduce the relationship between the number of vertices V, the number of edges E, and the number of regions F in a plane graph;

(3) It is now known that a certain plane graph has 999 vertices and encloses 999 regions. Try to determine the number of edges of this plane graph based on the above relationship.