CC(=O)NC1C(OCc2ccccc2)OC(CO)C(O)C1OC(C)C(=O)N[C@@H](C)C(=O)N[C@H](CCC(=O)OCCNc1c2ccccc2nc2cccc([N+](=O)[O-])c12)C(N)=O
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?