Using O=C1CCC(=O)N1Br, Cc1cc(C(Cl)=C(Cl)Cl)cc(C(Cl)=C(Cl)Cl)c1 to produce ClC(Cl)=C(Cl)c1cc(CBr)cc(C(Cl)=C(Cl)Cl)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.