Using CC(S)C(O)(Cn1cncn1)c1ccc(F)cc1F to produce CC(SSC(C)C(O)(Cn1cncn1)c1ccc(F)cc1F)C(O)(Cn1cncn1)c1ccc(F)cc1F, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.