a-a a-b aaa aab aaf aak aam aan aao aar ab- aba abb abf abk abm abn abo abr af- afa afb aff afk afm afn afo afr aka akb akk akm akn ako akr ama amb amf amk amm amn amo amr an- ana anb anf ank anm ann ano anr aoa aob aof aok aom aon aoo aor ar- ara arb arf ark arm arn aro arr baa bab baf bak bam ban bao bar bba bbb bbf bbk bbm bbn bbo bbr bfa bfb bff bfm bfn bfo bfr bka bkb bkf bkk bkm bkn bko bkr bma bmb bmf bmk bmm bmn bmo bmr bna bnb bnf bnk bnn bno bnr boa bob bof bok bom bon boo bor bra brb brf brk brm brn bro brr faa fab faf fak fam fan fao far fba fbb fbf fbk fbm fbn fbo fbr ffa fff ffk ffm ffn ffo ffr fka fkb fkf fkk fkm fma fmb fmf fmm fmn fmo fmr fna fnb fnf fnk fnm fnn fnr foa fob fof fok fom fon foo for fra frb frf frk frm frn fro frr ka- kaa kab kaf kak kam kan kao kar kba kbb kbf kbk kbm kbn kbo kbr kfa kff kfm kfo kkb kkk kkm kkn kkr kma kmb kmf kmk kmm kmo kn- kna knf knk knm knn kno knr koa kob kof kok kom kon koo kor kra krf krk krn kro krr m-f m-o m-r maa mab maf mak mam man mao mar mba mbb mbf mbk mbm mbo mbr mfa mfb mff mfm mfn mfo mfr mka mkb mkk mkm mkn mko mkr mma mmb mmf mmk mmm mmn mmo mmr mna mnb mnf mnk mnm mnn mno mnr moa mob mof mok mom mon moo mor mra mrb mrf mrk mrm mrn mro mrr naa nab naf nak nam nan nao nar nba nbb nbf nbk nbm nbn nbo nbr nfa nfb nff nfk nfn nfo nfr nka nkf nkk nkm nkn nko nkr nma nmb nmk nmm nmn nmo nmr nna nnb nnf nnk nnm nnn nno no- noa nob nof nok nom non noo nor nra nrb nrf nrk nrm nrn nro nrr oaa oab oaf oak oam oan oao oar ob- oba obb obf obk obm obn obo obr of- ofa ofb off ofm ofn ofo ofr oka okb okk oko okr om- oma omb omf omm omn omo omr on- ona onb onf onk onn ono onr oo- ooa oob oof ook oom oon ooo oor or- ora orb orf ork orm orn oro orr ra- raa rab raf rak ram ran rao rar rba rbb rbf rbk rbm rbn rbo rbr rfa rfb rff rfk rfm rfn rfo rfr rkb rkf rkk rkm rko rma rmb rmf rmm rmn rmo rmr rna rnb rnm rnn rno rnr roa rob rof rok rom ron roo ror rra rrb rrf rrk rrm rrn rrr