fff ffg ffi ffs fft fgf fgg fgi fgs fgt fif fig fii fis fit fsf fsg fsi fss fst ftf ftg fti fts ftt gff gfi gfs gft ggg ggi ggs ggt gif gig gii gis git gsf gsg gsi gss gst gtf gtg gti gts gtt i-f iff ifg ifi ifs ift igf igg igi igs igt iif iii iis iit is- isf isg isi iss ist itf itg iti its itt sff sfg sfi sfs sft sgf sgg sgi sgs sgt sif sig sii sis sit ss- ssf ssg ssi sss sst stf stg sti sts stt tff tfg tfi tfs tft tgf tgg tgi tgs tgt tif tig tii tis tit tsf tsg tsi tss tst ttf ttg tti tts ttt