a-a a-b a-c a-z aaa aab aac aak aao aar aaz ab- aba abb abc abk abo abr abz ac- aca acb acc ack aco acr acz aka akb akc akk ako akr aoa aob aoc aok aoo aor ar- ara arb arc ark aro arr arz az- aza azb azo azz baa bab bac bak bao bar baz bba bbb bbc bbk bbo bbr bca bcb bcc bck bco bcr bcz bka bkb bkc bkk bko bkr boa bob boc bok boo bor boz bra brb brk bro brr brz bza bzo bzr bzz c-- caa cab cac cak cao car caz cba cbb cbc cbk cbo cbr cbz cca ccb ccc cck cco ccr ccz cka ckb ckc cko co- coa cob coc cok coo cor coz cra crb crc crk cro crr crz cz- czc czk czo k-z ka- kaa kab kac kak kao kar kaz kba kbb kbc kbk kbo kbr kbz kca kcb kcc kck kcr kkb kkc kkk kkr koa kob koc kok koo kor koz kra krc krk kro krr kzo oaa oab oac oak oao oar ob- oba obb obc obk obo obr oc- oca ocb occ ock oco ocr ocz oka okb okc okk oko okr oo- ooa oob ooc ook ooo oor or- ora orb orc ork oro orr orz oza ozo ozz ra- raa rab rac rak rao rar raz rba rbb rbc rbk rbo rbr rca rcb rcc rco rcr rkb rkc rkk rko rkz roa rob roc rok roo ror roz rra rrb rrc rrk rrr rza rzb rzo zaa zab zac zak zao zar zaz zbb zbc zbr zco zka zo- zoa zob zoc zok zoo zor zro zzr zzz