Using CCCC[Sn](CCCC)(CCCC)c1nccs1, FC(F)(F)c1cnn2c(-c3cccc(Br)c3)cnc2n1 to produce FC(F)(F)c1cnn2c(-c3cccc(-c4nccs4)c3)cnc2n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.