a-a a-b a-t aaa aab aae aag aas aat ab- aba abb abe abg abs abt aea aeb aee aeg aes aet ag- aga agb age agg ags agt as- asa asb ase asg ass ast at- ata atb ate atg ats att baa bab bae bag bas bat bba bbb bbe bbg bbs bbt be- bea beb bee beg bes bet bga bgb bge bgg bgs bgt bsa bsb bse bsg bss bst bta btb bte btg bts btt eaa eab eae eag eas eat eba ebb ebe ebg ebs ebt eea eeb eee eeg ees eet ega egb ege egg egs egt es- esa esb ese esg ess est eta etb ete etg ets ett gaa gab gae gag gas gat gba gbe gbg gbs gbt ge- gea geb gee geg ges get gga ggb ggg ggs ggt gsa gsb gse gsg gss gst gta gtb gte gtg gts gtt saa sab sae sag sas sat sba sbb sbe sbg sbs sbt se- sea seb see seg ses set sga sgb sge sgg sgs sgt ss- ssa ssb sse ssg sss sst sta stb ste stg sts stt taa tab tae tag tas tat tba tbb tbe tbg tbs tbt te- tea teb tee teg tes tet tga tgb tge tgg tgs tgt tsa tsb tse tsg tss tst tta ttb tte ttg tts ttt