a-a a-b aaa aab aae aag aah aan ab- aba abb abe abg abh abn aea aeb aee aeg aeh aen ag- aga agb age agg agh agn aha ahb ahe ahg ahh ahn an- ana anb ane ang anh ann baa bab bae bag bah ban bba bbb bbe bbg bbh bbn be- bea beb bee beg beh ben bga bgb bge bgg bgh bgn bha bhb bhe bhg bhh bna bnb bne bng bnn eaa eab eae eag eah ean eba ebb ebe ebg ebh ebn eea eeb eee eeg een ega egb ege egg egh egn eha ehb ehe ehg ehh ehn en- ena enb ene eng enh enn gaa gab gae gag gah gan gba gbe gbg gbh gbn ge- gea geb gee geg geh gen gga ggb ggg ggh ggn gha ghb ghe ghg ghh ghn gna gnb gne gnn haa hab hae hag hah han hba hbb hbe hbg hbh hbn he- hea heb hee heg heh hen hga hgb hge hgg hgh hgn hha hhb hhe hhg hhh hhn hna hnb hne hng hnh hnn naa nab nae nag nah nan nba nbb nbe nbg nbn ne- nea neb nee neg neh nen nga ngb nge ngg ngh ngn nha nhb nhe nhg nhh nhn nna nnb nne nng nnh nnn