COc1cc([C@@H]2c3cc4c(cc3[C@@H](Nc3ccccc3C(=O)c3ccccc3)[C@H]3COC(=O)[C@@H]32)OCO4)cc(OC)c1OC
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?