C[C@H]([C@@H](N)C(=O)N[C@@H](C(=O)O)[C@@H]1O[C@H](n2ccc(=O)[nH]c2=O)[C@@H](O)[C@H]1O)[C@@H](O)c1ccc(O)cn1
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?