fff ffi ffp ffs fft fif fii fip fis fit fpi fpp fps fpt fsf fsi fsp fss fst ftf fti ftp fts ftt i-f iff ifi ifp ifs ift iif iii iip iis iit ipf ipi ipp ips ipt is- isf isi isp iss ist itf iti itp its itt p-p pff pfi pfp pfs pft pif pii pip pis pit ppf ppi ppp pps ppt ps- psf psi psp pss pst pt- ptf pti ptp pts ptt sff sfi sfp sfs sft sif sii sip sis sit spf spi spp sps spt ss- ssf ssi ssp sss sst stf sti stp sts stt tff tfi tfp tfs tft tif tii tip tis tit tpf tpi tpp tps tpt tsf tsi tsp tss tst ttf tti ttp tts ttt