bbb bbf bbg bbi bbs bfb bff bfg bfi bfs bgb bgf bgg bgi bgs bi- bib bif big bii bis bsb bsf bsg bsi bss fbb fbf fbg fbi fbs fff ffg ffi ffs fgb fgf fgg fgi fgs fib fif fig fii fis fsb fsf fsg fsi fss gbf gbg gbi gbs gfb gff gfi gfs ggb ggg ggi ggs gib gif gig gii gis gsb gsf gsg gsi gss i-f ibb ibf ibg ibi ibs ifb iff ifg ifi ifs igb igf igg igi igs iib iif iii iis is- isb isf isg isi iss sbb sbf sbg sbi sbs sfb sff sfg sfi sfs sgb sgf sgg sgi sgs sib sif sig sii sis ss- ssb ssf ssg ssi sss