NCCC[C@@H](CC(=O)N[C@@H]1CCCC[C@H]1C(=O)N[C@H](CC(=O)N[C@@H](CCC(=O)O)CC(=O)O)Cc1c[nH]c2ccccc12)NC(=O)C[C@H](CO)NC(=O)[C@@H]1CCCC[C@H]1N
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?