a-a a-b aaa aab aaf aag aak aan aao ab- aba abb abf abg abk abn abo af- afa afb aff afg afk afn afo ag- aga agb agf agg agk agn ago aka akb akg akk akn ako an- ana anb anf ang ank ann ano aoa aob aof aog aok aon aoo baa bab baf bag bak ban bao bba bbb bbf bbg bbk bbn bbo bfa bfb bff bfg bfn bfo bga bgb bgf bgg bgk bgn bgo bka bkb bkf bkg bkk bkn bko bna bnb bnf bng bnk bnn bno boa bob bof bog bok bon boo faa fab faf fag fak fan fao fba fbb fbf fbg fbk fbn fbo ffa fff ffg ffk ffn ffo fga fgb fgf fgg fgn fka fkb fkf fkg fkk fna fnb fnf fng fnk fnn foa fob fof fog fok fon foo gaa gab gaf gag gak gan gao gba gbf gbg gbk gbn gbo gfa gfb gff gfk gfo gga ggb ggg ggn ggo gka gkb gkn gko gna gnb gnf gnn gno goa gob gof gog gok gon goo ka- kaa kab kaf kag kak kan kao kba kbb kbf kbk kbn kbo kfa kff kfg kfo kga kgb kgf kgo kkb kkk kkn kn- kna knf kng knk knn kno koa kob kof kog kok kon koo naa nab naf nag nak nan nao nba nbb nbf nbg nbk nbn nbo nfa nfb nff nfk nfn nfo nga ngb ngf ngg ngk ngn ngo nka nkf nkk nkn nko nna nnb nnf nng nnk nnn nno no- noa nob nof nog nok non noo oaa oab oaf oag oak oan oao ob- oba obb obf obg obk obn obo of- ofa ofb off ofg ofn ofo oga ogf ogg ogn ogo oka okb okg okk oko on- ona onb onf ong onk onn ono oo- ooa oob oof oog ook oon ooo