['CCNCC#N', 'O=Cc1ccc([N+](=O)[O-])cc1', 'CC', 'N#CCNC(=O)c1ccc([N+](=O)[O-])cc1', 'CC#N', 'CCNC(=O)c1ccc([N+](=O)[O-])cc1', 'CCN(C=O)CC#N', 'O=[N+]([O-])c1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.