Using Nc1ncnn2c(-c3cccc(CO)c3)cc(-c3ccc4cn(Cc5ccccc5)nc4c3)c12, BrC(Br)(Br)Br to produce Nc1ncnn2c(-c3cccc(CBr)c3)cc(-c3ccc4cn(Cc5ccccc5)nc4c3)c12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.