CC1CC[C@@]23CCC4(C)[C@@]5(C)CCC6C(C)(C)C(=O)CC[C@@]6(C)C5C=C[C@@]4(OC2=O)C3C1C
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?