Using O=C(O)Cn1c(=O)c(=O)[nH]c2cc(Br)c(Br)cc21, Nc1cccc([N+](=O)[O-])c1 to produce O=C(O)Cn1c(=O)c(=O)[nH]c2c([N+](=O)[O-])c(Br)c(Br)cc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.