['CC#N', 'O=C1CNC(=O)N1c1cccc(C(F)(F)F)c1', 'FC(F)F', 'N#CCN1CC(=O)N(c2ccccc2)C1=O', 'N#CCN1CC(=O)NC1=O', 'FC(F)(F)c1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1CNC(=O)N1c1ccccc1.