CC1(C)C2CCC1(C)[C@H](n1c(=O)n([C@@H]3CC4CCC3(C)C4(C)C)c(=O)n([C@@H]3CC4CCC3(C)C4(C)C)c1=O)C2
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?