COC(=O)[C@H](Cc1ccccc1)NC(=O)N(CCN(CCC#N)C(=O)N[C@H](C(=O)OC)C(C)C)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?