Using Cc1c(Br)cc([N+](=O)[O-])cc1Br, O=C1CCC(=O)N1Br to produce O=[N+]([O-])c1cc(Br)c(CBr)c(Br)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.