NC(=O)c1cc[n+](CC2=C(C(=O)[O-])N3C(=O)C(NC(=O)C(c4ccccc4)S(=O)(=O)[O-])C3SC2)cc1.[Na+]
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?