['NCC(F)(F)F', 'O=CCn1cnc2c(Cl)cc(Cl)cc2c1=O', 'CC(F)(F)F', 'NC(=O)Cn1cnc2c(Cl)cc(Cl)cc2c1=O', 'CC(=O)NCC(F)(F)F', 'O=c1[nH]cnc2c(Cl)cc(Cl)cc12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1[nH]cnc2ccccc12.