f--k ffff ffrr ffss fftf frst fssf ftrs ftsr fuff fufu fukk fuku fur- furr furs furt fusk fuss fust fusu futs futu kfff kffk kfrr kfrs kfru kfsk kfsr kfst kftk kftt kftu kfut kkfr kkfs kkft kkkk kkrf kkrk kkrr kkrs kkrt kksf kksr kkss kkst kksu kktk kkts kktu kkus kkut kkuu krff krfs krft krkk krkr krks krku krrf krrk krrr krrs krrt krsf krsk krsr krss krst krsu krtk krtr krts kruf kruk krur ksfr ksft kskf kskk kskr ksks ksku ksrf ksrr ksrs ksrt kssr ksss ksst kssu kstk kstr ksts kstt kstu ksut ksuu ktfs ktkk ktkr ktks ktkt ktku ktrf ktrk ktrr ktrs ktrt ktru ktsf ktsr ktst ktsu kttf kttk kttr ktts kttt kttu ktuf kuff kufr kukk kuks kuku kurk kurr kurs kurt kuru kusf kust kusu kutf kutr kuts kutt kutu kuuk kuur kuuu rkkf rkss rkts rrrr rsts rstu rtss rtts ruff ruft rukk ruku rurs ruru rusk russ rust rusu ruts rutt rutu sfss sfsu sfts skrt skss skur skut srtr ssrs sssf ssss ssts stfu stks strk strs stru stsf stss sttr stuf stuk stur stus stut suf- suff sufr sufs sufu suks suku sur- surf surr surs surt suru sus- susk suss sust susu sutu suus tfrs tfss tkts trfr trst trtr truk trus trut truu tsks tssf tssr tsst tsts ttff ttss tttt tuff tuft tufu tuks turf turk turr turs turt turu tusk tuss tust tuts tutt tutu ufuk ukur urff urft urss ursu urts uruk urur urus urut us-k usfs ussf ussr usss usst ussu usts usus uttu uutf uuuu