['O=CCCC(=O)O', 'CCCSc1nnc(N)s1', 'CCC', 'O=C(O)CCC(=O)Nc1nnc(S)s1', 'NC(=O)CCC(=O)O', 'CCCSc1nncs1', 'CCCS', 'O=C(O)CCC(=O)Nc1nncs1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nncs1.