O=C1[C@H]2[C@@H](C(=O)N1C1CCCCC1)[C@@H](c1ccc(F)cc1)N1C(=O)N(c3cccc(Br)c3)C(=O)[C@@]21Cc1ccccc1
Hydrogen bond acceptor is the chemical compound which contains the lone electron pairs that participate in the hydrogen bond formation. How many hydrogen bond acceptors does the molecule contain?