['CCC', 'CSc1nc(N)c2cnn(CCN)c2n1', 'CCCN', 'CSc1ncc2cnn(CCN)c2n1', 'CCN', 'CCCNc1nc(SC)nc2[nH]ncc12', 'CS', 'CCCNc1ncnc2c1cnn2CCN']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ncc2cn[nH]c2n1.