a-a a-b aaa aab aaf aag aak aan aao aas ab- aba abb abf abg abk abn abo abs af- afa afb aff afg afk afn afo afs ag- aga agb agf agg agk agn ago ags aka akb akg akk akn ako aks an- ana anb anf ang ank ann ano ans aoa aob aof aog aok aon aoo aos as- asa asb asf asg ask asn aso ass baa bab baf bag bak ban bao bas bba bbb bbf bbg bbk bbn bbo bbs bfa bfb bff bfg bfn bfo bfs bga bgb bgf bgg bgk bgn bgo bgs bka bkb bkf bkg bkk bkn bko bks bna bnb bnf bng bnk bnn bno bns boa bob bof bog bok bon boo bos bsa bsb bsf bsg bsk bsn bso bss faa fab faf fag fak fan fao fas fba fbb fbf fbg fbk fbn fbo fbs ffa fff ffg ffk ffn ffo ffs fga fgb fgf fgg fgn fgs fka fkb fkf fkg fkk fna fnb fnf fng fnk fnn fns foa fob fof fog fok fon foo fos fsa fsb fsf fsg fsk fsn fso fss gaa gab gaf gag gak gan gao gas gba gbf gbg gbk gbn gbo gbs gfa gfb gff gfk gfo gfs gga ggb ggg ggn ggo ggs gka gkb gkn gko gks gna gnb gnf gnn gno gns goa gob gof gog gok gon goo gos gsa gsb gsf gsg gsk gsn gso gss ka- kaa kab kaf kag kak kan kao kas kba kbb kbf kbk kbn kbo kbs kfa kff kfg kfo kfs kga kgb kgf kgo kgs kkb kkk kkn kks kn- kna knf kng knk knn kno koa kob kof kog kok kon koo kos ksa ksb ksf ksg ksk ksn kso kss naa nab naf nag nak nan nao nas nba nbb nbf nbg nbk nbn nbo nbs nfa nfb nff nfk nfn nfo nfs nga ngb ngf ngg ngk ngn ngo ngs nka nkf nkk nkn nko nks nna nnb nnf nng nnk nnn nno nns no- noa nob nof nog nok non noo nos nsa nsb nsf nsg nsk nsn nso nss oaa oab oaf oag oak oan oao oas ob- oba obb obf obg obk obn obo obs of- ofa ofb off ofg ofn ofo ofs oga ogf ogg ogn ogo ogs oka okb okg okk oko oks on- ona onb onf ong onk onn ono ons oo- ooa oob oof oog ook oon ooo oos os- osa osb osf osg osk osn oso oss saa sab saf sag sak san sao sas sba sbb sbf sbg sbk sbn sbo sbs sfa sfb sff sfg sfk sfn sfo sfs sga sgb sgf sgg sgk sgn sgo sgs sk- ska skb skf skg skk sko sks sna snb snf sng snk snn sno sns soa sob sof sog sok son soo sos ss- ssa ssb ssf ssg ssk ssn sso sss