Using O=C1CCC(=O)N1Br, O=c1n(-c2ccc(F)cc2)ccc2nc(CCl)cn12 to produce O=c1n(-c2ccc(F)cc2)ccc2nc(CCl)c(Br)n12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.