COc1ccc(C(=O)C(CC2C(=O)CC(C)(C)C(C(=O)C(=O)Nc3c(C)cccc3C)C2=O)c2ccc(OC)cc2)cc1
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?