COc1ccc(-c2cc(=O)oc3c(C)c(OC(C)C(=O)N4C[C@@H]5C[C@H](C4)Cn4c5cccc4=O)ccc23)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?