CC(C)(C)OC(=O)CC[C@@H](C(=O)N1CCN(C(=O)OC(C)(C)C)CC1)n1cc(C(Cc2ccc(O)cc2)NC(=O)OC(C)(C)C)nn1
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?