a-a a-b a-i a-t aaa aab aai aak aao aat ab- aba abb abi abk abo abt ai- aia aib aii aik aio ait aka akb aki akk ako aoa aob aoi aok aoo aot at- ata atb ati ato att baa bab bai bak bao bat bba bbb bbi bbk bbo bbt bi- bia bib bii bik bio bit bka bkb bkk bko bkt boa bob boi bok boo bot bta btb bti btk bto btt ia- iaa iab iai iao iat iba ibb ibi ibk ibo ibt iia iib iii iio iit ika ikb iki ikk iko ikt io- ioa iob ioi ioo iot ita itb iti itk ito itt k-t ka- kaa kab kai kak kao kat kba kbb kbi kbk kbo kia kib kii kik kio kit kkb kki kkk kkt koa kob koi kok koo kot kta ktb ktk kto ktt o-i oaa oab oai oak oao oat ob- oba obb obi obk obo obt oia oib oii oik oio oit oka okb oki okk oko oo- ooa oob ooi ook ooo oot ot- ota otb oti otk oto ott taa tab tai tak tao tat tba tbb tbi tbk tbo tbt tia tib tii tik tio tit tka tkb tkk tko tkt to- toa tob toi tok too tot tta ttb tti ttk tto ttt