COC(=O)[C@@]1(Cc2ccc(OC)cc2)[C@H]2c3cc(C(=O)N4CCCC4)n(CCO)c3C[C@H]2CN1C(=O)c1ccccc1
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?