['Cc1ccccc1', 'Nc1cc(C(F)(F)F)n[nH]1', 'FC(F)F', 'Nc1ccnn1Cc1ccccc1', 'c1ccccc1', 'Cn1nc(C(F)(F)F)cc1N']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(Cn2cccn2)cc1.