O=c1[nH]c2c(N/N=C/c3ccc([N+](=O)[O-])o3)c([N+](=O)[O-])c(N/N=C/c3ccc([N+](=O)[O-])o3)c([N+](=O)[O-])c2[nH]1
Molecules possible for drug usually have no more than 5 Hydrogen bond acceptor. How many hydrogen bond acceptors does the molecule have?