a-a a-c aaa aac aae aan aao aax ac- aca acc ace acn aco acx aea aec aee aen aeo aex an- ana anc ane ann ano anx aoa aoc aoe aon aoo aox ax- axa axe axn axo axx c-- caa cac cae can cao cax cca ccc cce ccn cco ccx ce- cea cec cee cen ceo cex cn- cna cnc cne cnn cno cnx co- coa coc coe con coo cox cxc cxo cxx eaa eac eae ean eao eax ec- eca ecc ece ecn eco ecx eea eec eee een eeo eex en- ena enc ene enn eno eo- eoa eoc eoe eon eoo ex- exa exc exe exo exx naa nac nae nan nao nax nca ncc nce ncn nco ncx ne- nea nec nee nen neo nex nna nnc nne nnn nno no- noa noc noe non noo nox nxc oaa oac oae oan oao oax oc- oca occ ocn oco ocx oea oec oee oen oeo oex on- ona onc one onn ono onx oo- ooa ooc oon ooo oox ox- oxa oxc oxn oxo oxx xaa xac xan xcx xee xen xex xna xnc xno xoa xoc xon xoo xox xxo xxx