Using FC(F)=C(F)I, CCCC1CCC(C2CCC(c3ccc(I)cc3)CC2)CC1 to produce CCCC1CCC(C2CCC(c3ccc(C(F)=C(F)F)cc3)CC2)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.