O=C1/C(=C/c2ccccc2[N+](=O)[O-])N=C(c2ccccc2)N1C1Nc2cc3c(cc2S1)NC(N1C(=O)/C(=C/c2ccccc2[N+](=O)[O-])N=C1c1ccccc1)S3
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?