['NC1CCN(C2CC2)C1', 'O=[N+]([O-])c1cccc(F)c1', 'C1CCN(C2CC2)C1', 'Nc1ccc(F)cc1[N+](=O)[O-]', 'C1CC1', 'O=[N+]([O-])c1cc(F)ccc1NC1CCNC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(NC2CCN(C3CC3)C2)cc1.