a-a a-b aaa aab aag aak aan aao ab- aba abb abg abk abn abo ag- aga agb agg agk agn ago aka akb akg akk akn ako an- ana anb ang ank ann ano aoa aob aog aok aon aoo baa bab bag bak ban bao bba bbb bbg bbk bbn bbo bga bgb bgg bgk bgn bgo bka bkb bkg bkk bkn bko bna bnb bng bnk bnn bno boa bob bog bok bon boo gaa gab gag gak gan gao gba gbg gbk gbn gbo gga ggb ggg ggn ggo gka gkb gkn gko gna gnb gnn gno goa gob gog gok gon goo ka- kaa kab kag kak kan kao kba kbb kbk kbn kbo kga kgb kgo kkb kkk kkn kn- kna kng knk knn kno koa kob kog kok kon koo naa nab nag nak nan nao nba nbb nbg nbk nbn nbo nga ngb ngg ngk ngn ngo nka nkk nkn nko nna nnb nng nnk nnn nno no- noa nob nog nok non noo oaa oab oag oak oan oao ob- oba obb obg obk obn obo oga ogg ogn ogo oka okb okg okk oko on- ona onb ong onk onn ono oo- ooa oob oog ook oon ooo