c-- ccc cce ccn cco ccx ce- cec cee cen ceo cex cn- cnc cne cnn cno cnx co- coc coe con coo cox cxc cxo cxx ec- ecc ece ecn eco ecx eec eee een eeo eex en- enc ene enn eno eo- eoc eoe eon eoo ex- exc exe exo exx ncc nce ncn nco ncx ne- nec nee nen neo nex nnc nne nnn nno no- noc noe non noo nox nxc oc- occ ocn oco ocx oec oee oen oeo oex on- onc one onn ono onx oo- ooc oon ooo oox ox- oxc oxn oxo oxx xcx xee xen xex xnc xno xoc xon xoo xox xxo xxx