a-a a-b a-i a-t aaa aab aai aak aan aao aar aat ab- aba abb abi abk abn abo abr abt ai- aia aib aii aik ain aio air ait aka akb aki akk akn ako akr an- ana anb ani ank ann ano anr ant aoa aob aoi aok aon aoo aor aot ar- ara arb ari ark arn aro arr art at- ata atb ati atn ato atr att baa bab bai bak ban bao bar bat bba bbb bbi bbk bbn bbo bbr bbt bi- bia bib bii bik bin bio bir bit bka bkb bkk bkn bko bkr bkt bna bnb bni bnk bnn bno bnr bnt boa bob boi bok bon boo bor bot bra brb bri brk brn bro brr brt bta btb bti btk btn bto btr btt ia- iaa iab iai ian iao iar iat iba ibb ibi ibk ibn ibo ibr ibt iia iib iii iin iio iir iit ika ikb iki ikk iko ikr ikt in- ina inb ini ink inn ino inr int io- ioa iob ioi ion ioo ior iot ir- ira irb iri irk irn iro irr irt ita itb iti itk itn ito itt k-t ka- kaa kab kai kak kan kao kar kat kba kbb kbi kbk kbn kbo kbr kia kib kii kik kin kio kir kit kkb kki kkk kkn kkr kkt kn- kna kni knk knn kno knr knt koa kob koi kok kon koo kor kot kra kri krk krn kro krr krt kta ktb ktk ktn kto ktr ktt n-i naa nab nai nak nan nao nar nat nba nbb nbi nbk nbn nbo nbr nbt nia nib nii nik nin nio nir nit nka nki nkk nkn nko nkr nkt nna nnb nni nnk nnn nno nnt no- noa nob noi nok non noo nor not nra nrb nri nrk nrn nro nrr nrt nta ntb nti ntk ntn nto ntr ntt o-i oaa oab oai oak oan oao oar oat ob- oba obb obi obk obn obo obr obt oia oib oii oik oin oio oir oit oka okb oki okk oko okr on- ona onb oni onk onn ono onr ont oo- ooa oob ooi ook oon ooo oor oot or- ora orb ori ork orn oro orr ort ot- ota otb oti otk otn oto otr ott ra- raa rab rai rak ran rao rar rat rba rbb rbi rbk rbn rbo rbr rbt ria rib rii rik rin rio rir rit rkb rkk rko rkt rna rnb rni rnn rno rnr rnt roa rob roi rok ron roo ror rot rra rrb rri rrk rrn rrr rrt rta rtb rti rtk rtn rto rtr rtt taa tab tai tak tan tao tar tat tba tbb tbi tbk tbn tbo tbr tbt tia tib tii tik tin tio tir tit tka tkb tkk tko tkr tkt tna tnb tni tnk tnn tno tnr tnt to- toa tob toi tok ton too tor tot tra trb tri trk trn tro trr trt tta ttb tti ttk ttn tto ttr ttt