a-a a-b a-i aaa aab aai aak aam aao aar aas ab- aba abb abi abk abm abo abr abs ai- aia aib aii aik aim aio air ais aka akb aki akk akm ako akr aks ama amb ami amk amm amo amr ams aoa aob aoi aok aom aoo aor aos ar- ara arb ari ark arm aro arr ars as- asa asb asi ask asm aso asr ass baa bab bai bak bam bao bar bas bba bbb bbi bbk bbm bbo bbr bbs bi- bia bib bii bik bim bio bir bis bka bkb bkk bkm bko bkr bks bma bmb bmi bmk bmm bmo bmr bms boa bob boi bok bom boo bor bos bra brb bri brk brm bro brr brs bsa bsb bsi bsk bsm bso bsr bss ia- iaa iab iai iam iao iar ias iba ibb ibi ibk ibm ibo ibr ibs iia iib iii iim iio iir iis ika ikb iki ikk iko ikr iks im- ima imb imi imm imo ims io- ioa iob ioi iom ioo ior ios ir- ira irb iri irk irm iro irr irs is- isa isb isi isk ism iso isr iss ka- kaa kab kai kak kam kao kar kas kba kbb kbi kbk kbm kbo kbr kbs kia kib kii kik kim kio kir kis kkb kki kkk kkm kkr kks kma kmb kmi kmk kmm kmo kms koa kob koi kok kom koo kor kos kra kri krk kro krr krs ksa ksb ksi ksk ksm kso ksr kss m-o m-r maa mab mai mak mam mao mar mas mba mbb mbi mbk mbm mbo mbr mbs mi- mia mib mii mik mim mio mir mis mka mkb mkk mkm mko mkr mks mma mmb mmi mmk mmm mmo mmr mms moa mob moi mok mom moo mor mos mra mrb mri mrk mrm mro mrr mrs msa msb msi msk msm mso msr mss o-i oaa oab oai oak oam oao oar oas ob- oba obb obi obk obm obo obr obs oia oib oii oik oim oio oir ois oka okb oki okk oko okr oks om- oma omb omi omm omo omr oms oo- ooa oob ooi ook oom ooo oor oos or- ora orb ori ork orm oro orr ors os- osa osb osi osk osm oso osr oss ra- raa rab rai rak ram rao rar ras rba rbb rbi rbk rbm rbo rbr rbs ria rib rii rik rim rio rir ris rkb rkk rkm rko rks rma rmb rmi rmm rmo rmr rms roa rob roi rok rom roo ror ros rra rrb rri rrk rrm rrr rrs rsa rsb rsi rsk rsm rso rsr rss saa sab sai sak sam sao sar sas sba sbb sbi sbk sbm sbo sbr sbs sia sib sii sik sim sio sir sis sk- ska skb ski skk skm sko skr sks sma smb smi smk smm smo smr sms soa sob soi sok som soo sor sos sr- sra srb sri srk srm sro srr srs ss- ssa ssb ssi ssk ssm sso ssr sss