“…According to Figure 2, the size of the set of vertices is 17, thus V={1,2,…,17} and the set of edges is: E ={(1,5), (2,5), (3,5), (4,5), (5,10),$ $ (6,10), (7,10), (8,10), (9,10), (11,13), (10,13), (10,14), (12,14), (13,15), (13,16), (14,17)}. The subset of delivering stages is D={15, 16, 17}.…”