a-a a-b aaa aab aak aam aan aao aas ab- aba abb abk abm abn abo abs aka akb akk akm akn ako aks ama amb amk amm amn amo ams an- ana anb ank anm ann ano ans aoa aob aok aom aon aoo aos as- asa asb ask asm asn aso ass baa bab bak bam ban bao bas bba bbb bbk bbm bbn bbo bbs bka bkb bkk bkm bkn bko bks bma bmb bmk bmm bmn bmo bms bna bnb bnk bnn bno bns boa bob bok bom bon boo bos bsa bsb bsk bsm bsn bso bss ka- kaa kab kak kam kan kao kas kba kbb kbk kbm kbn kbo kbs kkb kkk kkm kkn kks kma kmb kmk kmm kmo kms kn- kna knk knm knn kno koa kob kok kom kon koo kos ksa ksb ksk ksm ksn kso kss m-o maa mab mak mam man mao mas mba mbb mbk mbm mbo mbs mka mkb mkk mkm mkn mko mks mma mmb mmk mmm mmn mmo mms mna mnb mnk mnm mnn mno mns moa mob mok mom mon moo mos msa msb msk msm msn mso mss naa nab nak nam nan nao nas nba nbb nbk nbm nbn nbo nbs nka nkk nkm nkn nko nks nma nmb nmk nmm nmn nmo nms nna nnb nnk nnm nnn nno nns no- noa nob nok nom non noo nos nsa nsb nsk nsm nsn nso nss oaa oab oak oam oan oao oas ob- oba obb obk obm obn obo obs oka okb okk oko oks om- oma omb omm omn omo oms on- ona onb onk onn ono ons oo- ooa oob ook oom oon ooo oos os- osa osb osk osm osn oso oss saa sab sak sam san sao sas sba sbb sbk sbm sbn sbo sbs sk- ska skb skk skm sko sks sma smb smk smm smn smo sms sna snb snk snm snn sno sns soa sob sok som son soo sos ss- ssa ssb ssk ssm ssn sso sss