a-a a-b a-i a-t aaa aab aag aai aas aat ab- aba abb abg abi abs abt ag- aga agb agg agi ags agt ai- aia aib aig aii ais ait as- asa asb asg asi ass ast at- ata atb atg ati ats att baa bab bag bai bas bat bba bbb bbg bbi bbs bbt bga bgb bgg bgi bgs bgt bi- bia bib big bii bis bit bsa bsb bsg bsi bss bst bta btb btg bti bts btt gaa gab gag gai gas gat gba gbg gbi gbs gbt gga ggb ggg ggi ggs ggt gia gib gig gii gis git gsa gsb gsg gsi gss gst gta gtb gtg gti gts gtt ia- iaa iab iag iai ias iat iba ibb ibg ibi ibs ibt iga igb igg igi igs igt iia iib iii iis iit is- isa isb isg isi iss ist ita itb itg iti its itt saa sab sag sai sas sat sba sbb sbg sbi sbs sbt sga sgb sgg sgi sgs sgt sia sib sig sii sis sit ss- ssa ssb ssg ssi sss sst sta stb stg sti sts stt taa tab tag tai tas tat tba tbb tbg tbi tbs tbt tga tgb tgg tgi tgs tgt tia tib tig tii tis tit tsa tsb tsg tsi tss tst tta ttb ttg tti tts ttt