CC(C)(CO)[C@@H](O)C(=O)NCCC(=O)[O-].CC(C)(CO)[C@@H](O)C(=O)NCCC(=O)[O-].[Ca+2]
Aromatic rings (also known as aromatic compounds or arenes) are hydrocarbons which contain benzene, or some other related ring structure. How many aromatic rings does the molecule contain?