COC(=O)C1OC(=O)C2OC23[C@@]1(C)CCC1[C@@]3(C)C(OC(C)=O)CC2C(C)(C)C(=O)CC[C@@]21C
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?