['FC(F)F', 'CCc1cnn(-c2ccccn2)c1N', 'CC', 'Nc1cc(C(F)(F)F)nn1-c1ccccn1', 'c1ccncc1', 'CCc1c(C(F)(F)F)n[nH]c1N']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-n2cccn2)nc1.