Using O=C(c1ccccc1)C(Cl)C(COCc1ccccc1)OCc1ccccc1, BrBr to produce O=C(c1ccccc1)C(Cl)(Br)C(COCc1ccccc1)OCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.