fff ffm ffo ffs fft ffy fmf fmm fmo fms fmt fof fom foo fos fot foy fsf fsm fso fss fst ftf ftm fto fts ftt fty fy- fyo m-f m-o mff mfm mfo mfs mft mfy mmf mmm mmo mms mmt mof mom moo mos mot moy msf msm mso mss mst msy mtf mtm mto mts mtt my- myf mym myo mys myt of- off ofm ofo ofs oft om- omf omm omo oms omt omy oo- oof oom ooo oos oot os- osf osm oso oss ost ot- otf otm oto ots ott oyo oys sff sfm sfo sfs sft smf smm smo sms smt smy sof som soo sos sot soy ss- ssf ssm sso sss sst stf stm sto sts stt sty sy- sym sys syt tff tfm tfo tfs tft tmf tmm tmo tms tmt tmy to- tof tom too tos tot toy tsf tsm tso tss tst tsy ttf ttm tto tts ttt tty tyf tym tyo tys tyt yff yfm yfs yft ymm ymo yms ymt yof yom yoo yos yot yoy ysm yso yss yst ysy ytf ytm yto yts ytt yyf yys yyt yyy