CC(=O)Oc1cc2c[n+](C)c3c4cc(OC(C)=O)c(OC(C)=O)cc4ccc3c2cc1OC(C)=O.O=S(=O)([O-])F
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?