CN[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H](CCCCNC(=O)OCc1ccccc1)C(=O)NC1CCCc2ccccc21)C(C)C.O=CO
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?