COc1cc2[nH]c3c(c2cc1OC)CCN[C@@]31CC[C@@]2(CC3c4c(cc(OC)c(O)c42)CCN3C)C[C@@H]1OC
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?