CC(=O)Nc1ccc(OC(=O)N2CCN(/[N+]([O-])=N/Oc3ccc([N+](=O)[O-])cc3[N+](=O)[O-])CC2)cc1
Hydrogen bond acceptor is the chemical compound which contains the lone electron pairs that participate in the hydrogen bond formation. How many hydrogen bond acceptors does the molecule contain?