a-a a-b a-c a-z aaa aab aac aak aao aar aas aaz ab- aba abb abc abk abo abr abs abz ac- aca acb acc ack aco acr acs acz aka akb akc akk ako akr aks aoa aob aoc aok aoo aor aos ar- ara arb arc ark aro arr ars arz as- asa asb asc ask aso asr ass asz az- aza azb azo azs azz baa bab bac bak bao bar bas baz bba bbb bbc bbk bbo bbr bbs bca bcb bcc bck bco bcr bcs bcz bka bkb bkc bkk bko bkr bks boa bob boc bok boo bor bos boz bra brb brk bro brr brs brz bsa bsb bsc bsk bso bsr bss bza bzo bzr bzs bzz c-- caa cab cac cak cao car cas caz cba cbb cbc cbk cbo cbr cbs cbz cca ccb ccc cck cco ccr ccs ccz cka ckb ckc cko cks co- coa cob coc cok coo cor cos coz cra crb crc crk cro crr crs crz csa csb csc csk cso csr css csz cz- czc czk czo k-z ka- kaa kab kac kak kao kar kas kaz kba kbb kbc kbk kbo kbr kbs kbz kca kcb kcc kck kcr kcs kkb kkc kkk kkr kks koa kob koc kok koo kor kos koz kra krc krk kro krr krs ksa ksb ksc ksk kso ksr kss kzo oaa oab oac oak oao oar oas ob- oba obb obc obk obo obr obs oc- oca ocb occ ock oco ocr ocs ocz oka okb okc okk oko okr oks oo- ooa oob ooc ook ooo oor oos or- ora orb orc ork oro orr ors orz os- osa osb osc osk oso osr oss oza ozo ozs ozz ra- raa rab rac rak rao rar ras raz rba rbb rbc rbk rbo rbr rbs rca rcb rcc rco rcr rcs rkb rkc rkk rko rks rkz roa rob roc rok roo ror ros roz rra rrb rrc rrk rrr rrs rsa rsb rsc rsk rso rsr rss rza rzb rzo saa sab sac sak sao sar sas saz sba sbb sbc sbk sbo sbr sbs sca scb scc sck sco scr scs sk- ska skb skc skk sko skr sks soa sob soc sok soo sor sos soz sr- sra srb src srk sro srr srs ss- ssa ssb ssc ssk sso ssr sss ssz sza szr zaa zab zac zak zao zar zas zaz zbb zbc zbr zbs zco zcs zka zks zo- zoa zob zoc zok zoo zor zos zro zrs zsa zsz zzr zzs zzz