fff ffm ffo ffr ffs fft fmf fmm fmo fmr fms fmt fof fom foo for fos fot frf frm fro frr frs frt fsf fsm fso fsr fss fst ftf ftm fto ftr fts ftt m-f m-o m-r mff mfm mfo mfr mfs mft mmf mmm mmo mmr mms mmt mof mom moo mor mos mot mrf mrm mro mrr mrs mrt msf msm mso msr mss mst mtf mtm mto mtr mts mtt of- off ofm ofo ofr ofs oft om- omf omm omo omr oms omt oo- oof oom ooo oor oos oot or- orf orm oro orr ors ort os- osf osm oso osr oss ost ot- otf otm oto otr ots ott rff rfm rfo rfr rfs rft rmf rmm rmo rmr rms rmt rof rom roo ror ros rot rrf rrm rrr rrs rrt rsf rsm rso rsr rss rst rtf rtm rto rtr rts rtt sff sfm sfo sfr sfs sft smf smm smo smr sms smt sof som soo sor sos sot sr- srf srm sro srr srs srt ss- ssf ssm sso ssr sss sst stf stm sto str sts stt tff tfm tfo tfr tfs tft tmf tmm tmo tmr tms tmt to- tof tom too tor tos tot trf trm tro trr trs trt tsf tsm tso tsr tss tst ttf ttm tto ttr tts ttt