bbb bbf bbg bbi bbt bfb bff bfg bfi bft bgb bgf bgg bgi bgt bi- bib bif big bii bit btb btf btg bti btt fbb fbf fbg fbi fbt fff ffg ffi fft fgb fgf fgg fgi fgt fib fif fig fii fit ftb ftf ftg fti ftt gbf gbg gbi gbt gfb gff gfi gft ggb ggg ggi ggt gib gif gig gii git gtb gtf gtg gti gtt i-f ibb ibf ibg ibi ibt ifb iff ifg ifi ift igb igf igg igi igt iib iif iii iit itb itf itg iti itt tbb tbf tbg tbi tbt tfb tff tfg tfi tft tgb tgf tgg tgi tgt tib tif tig tii tit ttb ttf ttg tti ttt