a-a a-b a-c aaa aab aac aag aan aao aau ab- aba abb abc abg abn abo abu ac- aca acb acc acg acn aco acu ag- aga agb agc agg agn ago agu an- ana anb anc ang ann ano anu aoa aob aoc aog aon aoo aou au- aua aub auc aug aun auo b-u baa bab bac bag ban bao bau bba bbb bbc bbg bbn bbo bbu bca bcb bcc bcg bcn bco bcu bga bgb bgc bgg bgn bgo bgu bna bnb bnc bng bnn bno bnu boa bob boc bog bon boo bou bua bub buc bug bun buo buu c-- caa cab cac cag can cao cau cba cbb cbc cbg cbn cbo cbu cca ccb ccc ccg ccn cco ccu cga cgb cgc cgg cgn cgo cgu cn- cna cnb cnc cng cnn cno cnu co- coa cob coc cog con coo cou cua cub cuc cug cun cuo cuu gaa gab gac gag gan gao gau gba gbc gbg gbn gbo gbu gca gcb gcc gcg gcn gco gcu gga ggb ggc ggg ggn ggo ggu gna gnb gnc gnn gno gnu goa gob goc gog gon goo gou gu- gua gub guc gug gun guo guu naa nab nac nag nan nao nau nba nbb nbc nbg nbn nbo nbu nca ncb ncc ncg ncn nco ncu nga ngb ngc ngg ngn ngo ngu nna nnb nnc nng nnn nno nnu no- noa nob noc nog non noo nou nua nub nuc nug nun nuo nuu oaa oab oac oag oan oao oau ob- oba obb obc obg obn obo obu oc- oca ocb occ ocg ocn oco ocu oga ogc ogg ogn ogo on- ona onb onc ong onn ono onu oo- ooa oob ooc oog oon ooo ou- oua ouc oun ouo ua- uaa uab uac uag uan uao uau uba ubb ubc ubg ubn ubo ubu uca ucb ucc ucg ucn uco ucu uga ugb ugc ugg ugn ugo ugu un- una unb unc ung unn uno unu uoa uob uoc uog uon uoo uua uuc uug uun uuu