['c1nn[nH]n1', 'Cc1cccc(C(F)(F)F)c1', 'FC(F)F', 'c1ccc(Cc2nn[nH]n2)cc1', 'Cc1nn[nH]n1', 'FC(F)(F)c1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(Cc2nn[nH]n2)cc1.