a-a a-b a-i a-t aaa aab aai aak aan aao aas aat ab- aba abb abi abk abn abo abs abt ai- aia aib aii aik ain aio ais ait aka akb aki akk akn ako aks an- ana anb ani ank ann ano ans ant aoa aob aoi aok aon aoo aos aot as- asa asb asi ask asn aso ass ast at- ata atb ati atn ato ats att baa bab bai bak ban bao bas bat bba bbb bbi bbk bbn bbo bbs bbt bi- bia bib bii bik bin bio bis bit bka bkb bkk bkn bko bks bkt bna bnb bni bnk bnn bno bns bnt boa bob boi bok bon boo bos bot bsa bsb bsi bsk bsn bso bss bst bta btb bti btk btn bto bts btt ia- iaa iab iai ian iao ias iat iba ibb ibi ibk ibn ibo ibs ibt iia iib iii iin iio iis iit ika ikb iki ikk iko iks ikt in- ina inb ini ink inn ino ins int io- ioa iob ioi ion ioo ios iot is- isa isb isi isk isn iso iss ist ita itb iti itk itn ito its itt k-t ka- kaa kab kai kak kan kao kas kat kba kbb kbi kbk kbn kbo kbs kia kib kii kik kin kio kis kit kkb kki kkk kkn kks kkt kn- kna kni knk knn kno knt koa kob koi kok kon koo kos kot ksa ksb ksi ksk ksn kso kss kst kta ktb ktk ktn kto kts ktt n-i naa nab nai nak nan nao nas nat nba nbb nbi nbk nbn nbo nbs nbt nia nib nii nik nin nio nis nit nka nki nkk nkn nko nks nkt nna nnb nni nnk nnn nno nns nnt no- noa nob noi nok non noo nos not nsa nsb nsi nsk nsn nso nss nst nta ntb nti ntk ntn nto nts ntt o-i oaa oab oai oak oan oao oas oat ob- oba obb obi obk obn obo obs obt oia oib oii oik oin oio ois oit oka okb oki okk oko oks on- ona onb oni onk onn ono ons ont oo- ooa oob ooi ook oon ooo oos oot os- osa osb osi osk osn oso oss ost ot- ota otb oti otk otn oto ots ott saa sab sai sak san sao sas sat sba sbb sbi sbk sbn sbo sbs sbt sia sib sii sik sin sio sis sit sk- ska skb ski skk sko sks skt sna snb sni snk snn sno sns snt soa sob soi sok son soo sos sot ss- ssa ssb ssi ssk ssn sso sss sst sta stb sti stk stn sto sts stt taa tab tai tak tan tao tas tat tba tbb tbi tbk tbn tbo tbs tbt tia tib tii tik tin tio tis tit tka tkb tkk tko tks tkt tna tnb tni tnk tnn tno tns tnt to- toa tob toi tok ton too tos tot tsa tsb tsi tsk tsn tso tss tst tta ttb tti ttk ttn tto tts ttt