['O=Cc1ccc(F)cc1', 'COCCNC(=S)NCCN', 'CO', 'CCNC(=S)NCCNC(=O)c1ccc(F)cc1', 'CCOC', 'NC(=S)NCCNC(=O)c1ccc(F)cc1', 'COCCNC(N)=S', 'CCNC(=O)c1ccc(F)cc1', 'CCNC(=S)NCCOC', 'NC(=O)c1ccc(F)cc1', 'Fc1ccccc1', 'COCCNC(=S)NCCNC=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.