a-a a-b a-i a-t aaa aab aaf aag aai aat ab- aba abb abf abg abi abt af- afa afb aff afg afi aft ag- aga agb agf agg agi agt ai- aia aib aif aig aii ait at- ata atb atf atg ati att baa bab baf bag bai bat bba bbb bbf bbg bbi bbt bfa bfb bff bfg bfi bft bga bgb bgf bgg bgi bgt bi- bia bib bif big bii bit bta btb btf btg bti btt faa fab faf fag fai fat fba fbb fbf fbg fbi fbt ffa fff ffg ffi fft fga fgb fgf fgg fgi fgt fia fib fif fig fii fit fta ftb ftf ftg fti ftt gaa gab gaf gag gai gat gba gbf gbg gbi gbt gfa gfb gff gfi gft gga ggb ggg ggi ggt gia gib gif gig gii git gta gtb gtf gtg gti gtt i-f ia- iaa iab iaf iag iai iat iba ibb ibf ibg ibi ibt ifa ifb iff ifg ifi ift iga igb igf igg igi igt iia iib iif iii iit ita itb itf itg iti itt taa tab taf tag tai tat tba tbb tbf tbg tbi tbt tfa tfb tff tfg tfi tft tga tgb tgf tgg tgi tgt tia tib tif tig tii tit tta ttb ttf ttg tti ttt