O=C1C/C(=C/c2ccc(/C=C3/CC(=O)N(c4cccc(Br)c4)C3=O)cc2)C(=O)N1c1cccc(Br)c1
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?