['FC(F)C1CC1', 'NC1CCC12CCC2', 'FC(F)C1CC1', 'NC1(C(F)F)CC1', 'C1CC2(C1)CCC2', 'FCF', 'C1CC2(C1)CCC2NC1CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CC2(C1)CCC2NC1CC1.