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