Using CCOC(=O)Cc1ccc(N)c(Oc2cc(Br)cc(C#N)c2)c1F, Cl to produce CCOC(=O)Cc1ccc(Cl)c(Oc2cc(Br)cc(C#N)c2)c1F, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.