CC1=C(C(=O)Nc2ccc(Cl)c(Cl)c2)C(c2ccc([N+](=O)[O-])cc2)C(C(=O)Nc2ccc(Cl)c(Cl)c2)=C(C)N1
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?