Using O=C1NCc2c(-c3ccccc3Cl)cc(CO)cc2N1c1c(Cl)cccc1Cl, BrC(Br)(Br)Br to produce O=C1NCc2c(-c3ccccc3Cl)cc(CBr)cc2N1c1c(Cl)cccc1Cl, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.