CC(=O)OCC(OC(C)=O)C(OC(C)=O)C(OC(C)=O)C(=O)CNn1c(-c2ccc(C)cc2)nc2ccccc2c1=O
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?