Using BrC(Br)(Br)Br, C=Cc1cc(C)c(C=O)c2ccn(S(=O)(=O)c3ccc(C)cc3)c12 to produce C=Cc1cc(C)c(C=C(Br)Br)c2ccn(S(=O)(=O)c3ccc(C)cc3)c12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.