a-a a-c aaa aac aae aao aas aax ac- aca acc ace aco acs acx aea aec aee aeo aes aex aoa aoc aoe aoo aos aox as- asa asc ase aso ass asx ax- axa axe axo axs axx c-- caa cac cae cao cas cax cca ccc cce cco ccs ccx ce- cea cec cee ceo ces cex co- coa coc coe coo cos cox csa csc cse cso css csx cxc cxo cxs cxx eaa eac eae eao eas eax ec- eca ecc ece eco ecs ecx eea eec eee eeo ees eex eo- eoa eoc eoe eoo eos es- esa esc ese eso ess esx ex- exa exc exe exo exs exx oaa oac oae oao oas oax oc- oca occ oco ocs ocx oea oec oee oeo oes oex oo- ooa ooc ooo oos oox os- osa osc ose oso oss osx ox- oxa oxc oxo oxx saa sac sae sao sas sax sca scc sce sco scs scx se- sea sec see seo ses sex soa soc soe soo sos sox ss- ssa ssc sse sso sss ssx sxc sxs xaa xac xas xcx xee xes xex xoa xoc xoo xos xox xsa xsc xss xxo xxx