Using O=C1C(Br)=CC=C2C1=Cc1cc(Br)ccc12, BrC(Br)(Br)Br to produce BrC(Br)=C1c2cc(Br)ccc2-c2ccc(Br)cc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.