a-a a-b a-t aaa aab aae aaf aag aas aat ab- aba abb abe abf abg abs abt aea aeb aee aef aeg aes aet af- afa afb afe aff afg afs aft ag- aga agb age agf agg ags agt as- asa asb ase asf asg ass ast at- ata atb ate atf atg ats att baa bab bae baf bag bas bat bba bbb bbe bbf bbg bbs bbt be- bea beb bee bef beg bes bet bfa bfb bfe bff bfg bfs bft bga bgb bge bgf bgg bgs bgt bsa bsb bse bsf bsg bss bst bta btb bte btf btg bts btt eaa eab eae eaf eag eas eat eba ebb ebe ebf ebg ebs ebt eea eeb eee eef eeg ees eet ef- efa efb efe eff efg efs eft ega egb ege egf egg egs egt es- esa esb ese esf esg ess est eta etb ete etf etg ets ett faa fab fae faf fag fas fat fba fbb fbe fbf fbg fbs fbt fea feb fee fef feg fes fet ffa ffe fff ffg ffs fft fga fgb fge fgf fgg fgs fgt fsa fsb fse fsf fsg fss fst fta ftb fte ftf ftg fts ftt gaa gab gae gaf gag gas gat gba gbe gbf gbg gbs gbt ge- gea geb gee gef geg ges get gfa gfb gfe gff gfs gft gga ggb ggg ggs ggt gsa gsb gse gsf gsg gss gst gta gtb gte gtf gtg gts gtt saa sab sae saf sag sas sat sba sbb sbe sbf sbg sbs sbt se- sea seb see sef seg ses set sfa sfb sfe sff sfg sfs sft sga sgb sge sgf sgg sgs sgt ss- ssa ssb sse ssf ssg sss sst sta stb ste stf stg sts stt taa tab tae taf tag tas tat tba tbb tbe tbf tbg tbs tbt te- tea teb tee tef teg tes tet tfa tfb tfe tff tfg tfs tft tga tgb tge tgf tgg tgs tgt tsa tsb tse tsf tsg tss tst tta ttb tte ttf ttg tts ttt