C[C@]1(O)CC[C@H]2[C@H]3[C@H](CC[C@@]21C)[C@@]1(C)CCC(=O)C=C1C[C@H]3O
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?