COC(=O)C1=C[C@@H](C(=O)OC)[C@@H]2C3=C(C(=O)[C@@]2(C)NC(=O)c2ccccc2)[C@H](c2ccccc2)[C@@H]2C(=O)NC(=O)[C@@H]2[C@@H]3C1
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?