fff ffr ffs fft ffy frf frr frs frt fry fsf fsr fss fst ftf ftr fts ftt fty fy- rff rfr rfs rft rrf rrr rrs rrt rsf rsr rss rst rtf rtr rts rtt rty ry- ryf ryr rys ryy sff sfr sfs sft sr- srf srr srs srt sry ss- ssf ssr sss sst stf str sts stt sty sy- syr sys syt tff tfr tfs tft trf trr trs trt try tsf tsr tss tst tsy ttf ttr tts ttt tty tyf tyr tys tyt yff yfr yfs yft yrf yrs yrt ysr yss yst ysy ytf ytr yts ytt yyf yys yyt yyy