a-a a-b a-i a-t aaa aab aaf aag aai aas aat ab- aba abb abf abg abi abs abt af- afa afb aff afg afi afs aft ag- aga agb agf agg agi ags agt ai- aia aib aif aig aii ais ait as- asa asb asf asg asi ass ast at- ata atb atf atg ati ats att baa bab baf bag bai bas bat bba bbb bbf bbg bbi bbs bbt bfa bfb bff bfg bfi bfs bft bga bgb bgf bgg bgi bgs bgt bi- bia bib bif big bii bis bit bsa bsb bsf bsg bsi bss bst bta btb btf btg bti bts btt faa fab faf fag fai fas fat fba fbb fbf fbg fbi fbs fbt ffa fff ffg ffi ffs fft fga fgb fgf fgg fgi fgs fgt fia fib fif fig fii fis fit fsa fsb fsf fsg fsi fss fst fta ftb ftf ftg fti fts ftt gaa gab gaf gag gai gas gat gba gbf gbg gbi gbs gbt gfa gfb gff gfi gfs gft gga ggb ggg ggi ggs ggt gia gib gif gig gii gis git gsa gsb gsf gsg gsi gss gst gta gtb gtf gtg gti gts gtt i-f ia- iaa iab iaf iag iai ias iat iba ibb ibf ibg ibi ibs ibt ifa ifb iff ifg ifi ifs ift iga igb igf igg igi igs igt iia iib iif iii iis iit is- isa isb isf isg isi iss ist ita itb itf itg iti its itt saa sab saf sag sai sas sat sba sbb sbf sbg sbi sbs sbt sfa sfb sff sfg sfi sfs sft sga sgb sgf sgg sgi sgs sgt sia sib sif sig sii sis sit ss- ssa ssb ssf ssg ssi sss sst sta stb stf stg sti sts stt taa tab taf tag tai tas tat tba tbb tbf tbg tbi tbs tbt tfa tfb tff tfg tfi tfs tft tga tgb tgf tgg tgi tgs tgt tia tib tif tig tii tis tit tsa tsb tsf tsg tsi tss tst tta ttb ttf ttg tti tts ttt