COc1cc(O)c2c(=O)c3c(O[C@H]4O[C@@H](CO)[C@H](O)[C@@H](O)[C@@H]4O)ccc(O)c3oc2c1
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?