O=C1[C@H]2[C@@H](C(=O)N1c1ccccc1)[C@@H](C1CC1)N1C(=O)CN(Cc3ccccn3)C(=O)[C@@]21Cc1ccccc1
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?