CCN(CC)C(=O)[C@H]1C[C@H](CC(=O)NCCCN(C)C)C(=O)N2CCc3c([nH]c4ccc(Cl)cc34)[C@]12C
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?