a-a a-b a-i a-z aaa aab aai aak aao aas aaz ab- aba abb abi abk abo abs abz ai- aia aib aii aik aio ais aiz aka akb aki akk ako aks aoa aob aoi aok aoo aos as- asa asb asi ask aso ass asz az- aza azb azi azo azs azz baa bab bai bak bao bas baz bba bbb bbi bbk bbo bbs bi- bia bib bii bik bio bis biz bka bkb bkk bko bks boa bob boi bok boo bos boz bsa bsb bsi bsk bso bss bza bzo bzs bzz ia- iaa iab iai iao ias iaz iba ibb ibi ibk ibo ibs ibz iia iib iii iio iis ika ikb iki ikk iko iks io- ioa iob ioi ioo ios is- isa isb isi isk iso iss iza izi izo izz k-z ka- kaa kab kai kak kao kas kaz kba kbb kbi kbk kbo kbs kbz kia kib kii kik kio kis kiz kkb kki kkk kks koa kob koi kok koo kos koz ksa ksb ksi ksk kso kss kzo o-i oaa oab oai oak oao oas ob- oba obb obi obk obo obs oia oib oii oik oio ois oiz oka okb oki okk oko oks oo- ooa oob ooi ook ooo oos os- osa osb osi osk oso oss oza ozo ozs ozz saa sab sai sak sao sas saz sba sbb sbi sbk sbo sbs sia sib sii sik sio sis sk- ska skb ski skk sko sks soa sob soi sok soo sos soz ss- ssa ssb ssi ssk sso sss ssz sza szi zaa zab zai zak zao zas zaz zbb zbs zia zib zik zio zis ziz zka zks zo- zoa zob zoi zok zoo zos zsa zsi zsz zzs zzz