CN1C(=O)[C@H]2[C@@H](C1=O)[C@@H](C1CC1)N1C(=O)CN(Cc3ccc(-c4ccccc4)cc3)C(=O)[C@@]21C
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?