O=C1/C(=C/c2ccc(OC(=O)c3ccc(Cl)cc3)cc2)CCC/C1=C\c1ccc(OC(=O)c2ccc(Cl)cc2)cc1
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?