ffff ffrr ffss fftf fmsr fmss frsm frst frum fssf ftrs ftsr fuff fufu fums fur- furm furr furs furt fuss fust fusu futs futu mfrs mftf mmff mmmm mmms mmrf mmst mmsu mmts mmus mrtm mrts mrtt msff msfs msft msmm msms msmu msrt mssf mssm mssr msst mstr msts msus mtff mtrr mtss mtst mttr mtts muff mufu mumm mums mumu murr murs murt muru muss must musu muts mutt mutu muut rmst rmtu rrrr rrum rsts rstu rsum rtfm rtms rtss rtts ruff ruft rumm rums rumt rurs ruru russ rust rusu ruts rutt rutu sfmm sfss sfsu sfts smrf smrt smss smtu smur smus smut srtr ssrm ssrs sssf sssm ssss ssts stfu stms stmt strs stru stsf stsm stss sttr stuf stum stur stus stut suf- suff sufr sufs sufu sum- sums sumu sur- surf surr surs surt suru sus- suss sust susu sutu suum suus tfrs tfss tmtt trfm trfr trms trmu trst trtr trus trut truu tsfm tssf tssm tssr tsst tstm tsts tsum ttff ttms ttss tttt tuff tufm tuft tufu tums tumu turf turm turr turs turt turu tusm tuss tust tuts tutt tutu tuum ufms umff umms umsu umts umus umut urff urft urss ursu urts urum urur urus urut usfs usmm usms ussf ussr usss usst ussu ustm usts usus uttu uutf uuuu