['CO', 'O=C1/C(=C/c2ccccc2)CCc2[nH]c3ccc(F)cc3c21', 'COc1cccc(C)c1', 'O=C1CCCc2[nH]c3ccc(F)cc3c21']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1/C(=C/c2ccccc2)CCc2[nH]c3ccccc3c21.