a-a a-b a-i a-z aaa aab aai aak aao aar aaz ab- aba abb abi abk abo abr abz ai- aia aib aii aik aio air aiz aka akb aki akk ako akr aoa aob aoi aok aoo aor ar- ara arb ari ark aro arr arz az- aza azb azi azo azz baa bab bai bak bao bar baz bba bbb bbi bbk bbo bbr bi- bia bib bii bik bio bir biz bka bkb bkk bko bkr boa bob boi bok boo bor boz bra brb bri brk bro brr brz bza bzo bzr bzz ia- iaa iab iai iao iar iaz iba ibb ibi ibk ibo ibr ibz iia iib iii iio iir ika ikb iki ikk iko ikr io- ioa iob ioi ioo ior ir- ira irb iri irk iro irr iza izi izo izz k-z ka- kaa kab kai kak kao kar kaz kba kbb kbi kbk kbo kbr kbz kia kib kii kik kio kir kiz kkb kki kkk kkr koa kob koi kok koo kor koz kra kri krk kro krr kzo o-i oaa oab oai oak oao oar ob- oba obb obi obk obo obr oia oib oii oik oio oir oiz oka okb oki okk oko okr oo- ooa oob ooi ook ooo oor or- ora orb ori ork oro orr orz oza ozo ozz ra- raa rab rai rak rao rar raz rba rbb rbi rbk rbo rbr ria rib rii rik rio rir riz rkb rkk rko rkz roa rob roi rok roo ror roz rra rrb rri rrk rrr rza rzb rzo zaa zab zai zak zao zar zaz zbb zbr zia zib zik zio zir ziz zka zo- zoa zob zoi zok zoo zor zro zzr zzz