CCOC(=O)c1ccc(NC(=O)c2[nH]cnc2C(=O)N[C@@H](CCCCNC(=O)OC(C)(C)C)C(=O)OC(C)(C)C)cc1
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?