a-a a-b a-i a-t aaa aab aai aak aao aar aat ab- aba abb abi abk abo abr abt ai- aia aib aii aik aio air ait aka akb aki akk ako akr aoa aob aoi aok aoo aor aot ar- ara arb ari ark aro arr art at- ata atb ati ato atr att baa bab bai bak bao bar bat bba bbb bbi bbk bbo bbr bbt bi- bia bib bii bik bio bir bit bka bkb bkk bko bkr bkt boa bob boi bok boo bor bot bra brb bri brk bro brr brt bta btb bti btk bto btr btt ia- iaa iab iai iao iar iat iba ibb ibi ibk ibo ibr ibt iia iib iii iio iir iit ika ikb iki ikk iko ikr ikt io- ioa iob ioi ioo ior iot ir- ira irb iri irk iro irr irt ita itb iti itk ito itt k-t ka- kaa kab kai kak kao kar kat kba kbb kbi kbk kbo kbr kia kib kii kik kio kir kit kkb kki kkk kkr kkt koa kob koi kok koo kor kot kra kri krk kro krr krt kta ktb ktk kto ktr ktt o-i oaa oab oai oak oao oar oat ob- oba obb obi obk obo obr obt oia oib oii oik oio oir oit oka okb oki okk oko okr oo- ooa oob ooi ook ooo oor oot or- ora orb ori ork oro orr ort ot- ota otb oti otk oto otr ott ra- raa rab rai rak rao rar rat rba rbb rbi rbk rbo rbr rbt ria rib rii rik rio rir rit rkb rkk rko rkt roa rob roi rok roo ror rot rra rrb rri rrk rrr rrt rta rtb rti rtk rto rtr rtt taa tab tai tak tao tar tat tba tbb tbi tbk tbo tbr tbt tia tib tii tik tio tir tit tka tkb tkk tko tkr tkt to- toa tob toi tok too tor tot tra trb tri trk tro trr trt tta ttb tti ttk tto ttr ttt