Using O=C(O)C(Br)CCC(Br)C(=O)O, C1CNCCNCCNCCN1 to produce O=C(O)C(CCC(C(=O)O)N1CCNCCNCCNCC1)N1CCNCCNCCNCC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.