NC(=O)[C@H]1CC2(CC(c3cccc(NC(=O)COc4ccc(Cl)cc4)c3)=NO2)CN1C(=O)CC(c1ccccc1)c1ccccc1
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?