C[C@@H](C(=O)NCCc1c[nH]c2ccccc12)[C@H]1C[C@]1(C)[C@H](NC(=O)OCc1ccccc1)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?