NC(=O)[C@@H]1CC2(CC(c3cccc(NC(=O)CC(c4ccccc4)c4ccccc4)c3)=NO2)CN1C(=O)COc1ccc(Cl)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?