C[C@@H](CC(=O)O)OC1OC(COC(=O)C(C)(C)C)C(OC(=O)C(C)(C)C)C(OC(=O)C(C)(C)C)C1OC(=O)C(C)(C)C
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?