O=c1c2cc(S(=O)(=O)O)ccc2nc(COc2ccc(Oc3ccc(Cl)cc3Cl)cc2)n1-c1ccc(Oc2ccc(Cl)cc2)cc1Cl
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?