c-- ccc ccf ccn cco ccx cfc cff cfn cfo cfx cn- cnc cnf cnn cno cnx co- coc cof con coo cox cxc cxf cxo cxx fcc fcf fcn fco fcx ffc fff ffn ffo ffx fnc fnf fnn fnx foc fof fon foo fox fxx ncc ncf ncn nco ncx nfc nff nfn nfo nnc nnf nnn nno no- noc nof non noo nox nxc oc- occ ocf ocn oco ocx of- ofc off ofn ofo ofx on- onc onf onn ono onx oo- ooc oof oon ooo oox ox- oxc oxf oxn oxo oxx xcf xcx xfn xfx xnc xno xoc xof xon xoo xox xxo xxx