Agraph G Consists of a Nonempty Set V (G) of Objects Called Vertices and A(Possibly Empty) Set E (G) of Two Element Subsets of V (G), Called Edges. Theset V (G) Is Called the Vertex Set of G and E (G) Its Edge Set. the Number Ofvertices In a Graph G Is Called Its Order, and the Number of Edges Is Its Size.A Graph of Order P and Size Q Is Called a (P, Q)-Graph.