O=C(C1=C[C@@H]2[C@H]3C(=O)N(c4ccccc4Cl)C(=O)[C@H]3[C@@H](C(=O)c3ccc(Cl)cc3)N2C=C1)c1ccccc1
Hydrogen bond acceptor is the chemical compound which contains the lone electron pairs that participate in the hydrogen bond formation. This compound should contain a more electronegative atom (more electronegative than hydrogen) with lone electron pairs. Then it can attract protons from a donor. Moreover, the electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?