COC(=O)C1=C(C(=O)OC)[C@@H]2N(C)c3ccccc3[C@@]23C[C@@H](C(=O)OC)N(C(=O)CC(C)C)C3=N1
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?