1graph A { 2 node[shape="circle"] 3B [ style="filled", fillcolor="red" ]; 4G [ style="filled", fillcolor="red" ]; 5A [ style="filled", fillcolor="red" ]; 6A -- F[label="1"] 7A -- B[label="1"] 8A -- G[label="3"] 9B -- C[label="0"] 10B -- D[label="0"] 11B -- E[label="1"] 12C -- D[label="0"] 13E -- F[label="1"] 14G -- I[label="2"] 15G -- H[label="2"] 16H -- I[label="2"] 17} 18