O=C(O)c1cc(NC(=O)c2cccc(C(=O)Nc3cc(C(=O)O)cc(C(=O)O)c3)c2)cc(C(=O)O)c1
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?