O=S(=O)(O)c1cccc2ccc(O)c(/N=N\c3ccc(S(=O)(=O)c4ccc(/N=N/c5c(O)ccc6cccc(S(=O)(=O)O)c56)cc4)cc3)c12
Hydrogen bond acceptor is the chemical compound which contains the lone electron pairs that participate in the hydrogen bond formation. How many hydrogen bond acceptors does the molecule contain?