Using CSc1nc(N)nc(-c2ccc(Br)o2)c1C#N, C=C(OCC)[Sn](CCCC)(CCCC)CCCC to produce C=C(OCC)c1ccc(-c2nc(N)nc(SC)c2C#N)o1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.