CC1=C(C(=O)Nc2cc(=O)n(C)c(=O)n2C)C(c2ccco2)C(C(=O)Nc2cc(=O)n(C)c(=O)n2C)=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?