a-a a-b a-i aaa aab aai aak aan aao aar ab- aba abb abi abk abn abo abr ai- aia aib aii aik ain aio air aka akb aki akk akn ako akr an- ana anb ani ank ann ano anr aoa aob aoi aok aon aoo aor ar- ara arb ari ark arn aro arr baa bab bai bak ban bao bar bba bbb bbi bbk bbn bbo bbr bi- bia bib bii bik bin bio bir bka bkb bkk bkn bko bkr bna bnb bni bnk bnn bno bnr boa bob boi bok bon boo bor bra brb bri brk brn bro brr ia- iaa iab iai ian iao iar iba ibb ibi ibk ibn ibo ibr iia iib iii iin iio iir ika ikb iki ikk iko ikr in- ina inb ini ink inn ino inr io- ioa iob ioi ion ioo ior ir- ira irb iri irk irn iro irr ka- kaa kab kai kak kan kao kar kba kbb kbi kbk kbn kbo kbr kia kib kii kik kin kio kir kkb kki kkk kkn kkr kn- kna kni knk knn kno knr koa kob koi kok kon koo kor kra kri krk krn kro krr n-i naa nab nai nak nan nao nar nba nbb nbi nbk nbn nbo nbr nia nib nii nik nin nio nir nka nki nkk nkn nko nkr nna nnb nni nnk nnn nno no- noa nob noi nok non noo nor nra nrb nri nrk nrn nro nrr o-i oaa oab oai oak oan oao oar ob- oba obb obi obk obn obo obr oia oib oii oik oin oio oir oka okb oki okk oko okr on- ona onb oni onk onn ono onr oo- ooa oob ooi ook oon ooo oor or- ora orb ori ork orn oro orr ra- raa rab rai rak ran rao rar rba rbb rbi rbk rbn rbo rbr ria rib rii rik rin rio rir rkb rkk rko rna rnb rni rnn rno rnr roa rob roi rok ron roo ror rra rrb rri rrk rrn rrr