C[C@]12C[C@H](O)[C@H]3[C@@H](C[C@@H](O)C4=CC(=O)CC[C@@]43C)[C@@H]1CC[C@]2(O)C(=O)CO
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?