a-a a-c aaa aac aae aaf aak aao aas ac- aca acc ace acf ack aco acs aea aec aee aef aek aeo aes af- afa afc afe aff afk afo afs aka akc ake akk ako aks aoa aoc aoe aof aok aoo aos as- asa asc ase asf ask aso ass c-- caa cac cae caf cak cao cas cca ccc cce ccf cck cco ccs ce- cea cec cee cef cek ceo ces cfa cfc cfe cff cfk cfo cfs cka ckc cko cks co- coa coc coe cof cok coo cos csa csc cse csf csk cso css eaa eac eae eaf eak eao eas ec- eca ecc ece ecf eck eco ecs eea eec eee eef eek eeo ees ef- efa efc efe eff efo efs eka ekc eke ekf eko eks eo- eoa eoc eoe eof eok eoo eos es- esa esc ese esf esk eso ess faa fac fae faf fak fao fas fca fcc fce fcf fck fco fcs fea fec fee fef fek feo fes ffa ffc ffe fff ffk ffo ffs fka fkc fkf fkk foa foc foe fof fok foo fos fsa fsc fse fsf fsk fso fss ka- kaa kac kae kaf kak kao kas kca kcc kce kck kcs ke- kea kec kee kef kek keo kes kfa kfc kff kfo kfs kkc kke kkk kks koa koc koe kof kok koo kos ksa ksc kse ksf ksk kso kss oaa oac oae oaf oak oao oas oc- oca occ ocf ock oco ocs oea oec oee oef oeo oes of- ofa ofc ofe off ofo ofs oka okc oke okk oko oks oo- ooa ooc oof ook ooo oos os- osa osc ose osf osk oso oss saa sac sae saf sak sao sas sca scc sce scf sck sco scs se- sea sec see sef sek seo ses sfa sfc sfe sff sfk sfo sfs sk- ska skc ske skf skk sko sks soa soc soe sof sok soo sos ss- ssa ssc sse ssf ssk sso sss