a-a a-b aaa aab aak aam aan aao aar ab- aba abb abk abm abn abo abr aka akb akk akm akn ako akr ama amb amk amm amn amo amr an- ana anb ank anm ann ano anr aoa aob aok aom aon aoo aor ar- ara arb ark arm arn aro arr baa bab bak bam ban bao bar bba bbb bbk bbm bbn bbo bbr bka bkb bkk bkm bkn bko bkr bma bmb bmk bmm bmn bmo bmr bna bnb bnk bnn bno bnr boa bob bok bom bon boo bor bra brb brk brm brn bro brr ka- kaa kab kak kam kan kao kar kba kbb kbk kbm kbn kbo kbr kkb kkk kkm kkn kkr kma kmb kmk kmm kmo kn- kna knk knm knn kno knr koa kob kok kom kon koo kor kra krk krn kro krr m-o m-r maa mab mak mam man mao mar mba mbb mbk mbm mbo mbr mka mkb mkk mkm mkn mko mkr mma mmb mmk mmm mmn mmo mmr mna mnb mnk mnm mnn mno mnr moa mob mok mom mon moo mor mra mrb mrk mrm mrn mro mrr naa nab nak nam nan nao nar nba nbb nbk nbm nbn nbo nbr nka nkk nkm nkn nko nkr nma nmb nmk nmm nmn nmo nmr nna nnb nnk nnm nnn nno no- noa nob nok nom non noo nor nra nrb nrk nrm nrn nro nrr oaa oab oak oam oan oao oar ob- oba obb obk obm obn obo obr oka okb okk oko okr om- oma omb omm omn omo omr on- ona onb onk onn ono onr oo- ooa oob ook oom oon ooo oor or- ora orb ork orm orn oro orr ra- raa rab rak ram ran rao rar rba rbb rbk rbm rbn rbo rbr rkb rkk rkm rko rma rmb rmm rmn rmo rmr rna rnb rnm rnn rno rnr roa rob rok rom ron roo ror rra rrb rrk rrm rrn rrr