a-a a-b a-c aaa aab aac aag aah aan aao ab- aba abb abc abg abh abn abo ac- aca acb acc acg ach acn aco ag- aga agb agc agg agh agn ago aha ahb ahc ahg ahh ahn aho an- ana anb anc ang anh ann ano aoa aob aoc aog aoh aon aoo baa bab bac bag bah ban bao bba bbb bbc bbg bbh bbn bbo bca bcb bcc bcg bch bcn bco bga bgb bgc bgg bgh bgn bgo bha bhb bhc bhg bhh bho bna bnb bnc bng bnn bno boa bob boc bog boh bon boo c-- caa cab cac cag cah can cao cba cbb cbc cbg cbh cbn cbo cca ccb ccc ccg cch ccn cco cga cgb cgc cgg cgh cgn cgo ch- cha chb chc chg chh chn cho cn- cna cnb cnc cng cnh cnn cno co- coa cob coc cog coh con coo gaa gab gac gag gah gan gao gba gbc gbg gbh gbn gbo gca gcb gcc gcg gch gcn gco gga ggb ggc ggg ggh ggn ggo gha ghb ghc ghg ghh ghn gho gna gnb gnc gnn gno goa gob goc gog goh gon goo haa hab hac hag hah han hao hba hbb hbc hbg hbh hbn hbo hca hcb hcc hcg hch hcn hco hga hgb hgc hgg hgh hgn hgo hha hhb hhc hhg hhh hhn hho hna hnb hnc hng hnh hnn hno hoa hob hoc hog hoh hon hoo naa nab nac nag nah nan nao nba nbb nbc nbg nbn nbo nca ncb ncc ncg nch ncn nco nga ngb ngc ngg ngh ngn ngo nha nhb nhc nhg nhh nhn nna nnb nnc nng nnh nnn nno no- noa nob noc nog noh non noo oaa oab oac oag oah oan oao ob- oba obb obc obg obh obn obo oc- oca ocb occ ocg och ocn oco oga ogc ogg ogh ogn ogo oha ohc ohg ohh ohn oho on- ona onb onc ong onh onn ono oo- ooa oob ooc oog ooh oon ooo