['CC', 'CCNCCNc1nc2c(F)cccc2s1', 'CCNCC', 'CCNc1nc2c(F)cccc2s1', 'CCN(CC)CC', 'Nc1nc2c(F)cccc2s1', 'CCN(CC)CCN', 'Fc1cccc2scnc12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2scnc2c1.