O=C(CNc1ccccc1[N+](=O)[O-])Nn1cnc2ccc(S(=O)(=O)Nc3ccccc3[N+](=O)[O-])cc2c1=O
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?