Using NCCN, Nc1ncnc2c1nc(Br)n2[C@@H]1O[C@H](COP(=O)(O)O)[C@@H](O)[C@H]1O to produce NCCNc1nc2c(N)ncnc2n1[C@@H]1O[C@H](COP(=O)(O)O)[C@@H](O)[C@H]1O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.