bbb bbf bbi bbr bbs bbt bfb bff bfi bfr bfs bft bi- bib bif bii bir bis bit brb brf bri brr brs brt bsb bsf bsi bsr bss bst btb btf bti btr bts btt fbb fbf fbi fbr fbs fbt fff ffi ffr ffs fft fib fif fii fir fis fit frb frf fri frr frs frt fsb fsf fsi fsr fss fst ftb ftf fti ftr fts ftt i-f ibb ibf ibi ibr ibs ibt ifb iff ifi ifr ifs ift iib iif iii iir iis iit ir- irb irf iri irr irs irt is- isb isf isi isr iss ist itb itf iti its itt rbb rbf rbi rbr rbs rbt rfb rff rfi rfr rfs rft rib rif rii rir ris rit rrb rrf rri rrr rrs rrt rsb rsf rsi rsr rss rst rtb rtf rti rtr rts rtt sbb sbf sbi sbr sbs sbt sfb sff sfi sfr sfs sft sib sif sii sir sis sit sr- srb srf sri srr srs srt ss- ssb ssf ssi ssr sss sst stb stf sti str sts stt tbb tbf tbi tbr tbs tbt tfb tff tfi tfr tfs tft tib tif tii tir tis tit trb trf tri trr trs trt tsb tsf tsi tsr tss tst ttb ttf tti ttr tts ttt