O=S(=O)(O)c1cc(O)c2c(/N=N/c3ccc(Nc4ccccc4)c4c(S(=O)(=O)O)cccc34)cc(S(=O)(=O)O)cc2c1
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?