COc1ccc(C(=O)/C=C/c2ccc(OCCCOc3ccc(/C=C/C(=O)c4ccc(OC)c(OC)c4)cc3)cc2)cc1OC
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?