Using O=[N+]([O-])O, COc1c(F)c(C(=O)O)cc(F)c1Br to produce COc1c(F)c(C(=O)O)c([N+](=O)[O-])c(F)c1Br, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.