pppp ppps ppru ppss ppts pptt ppur prps prrs prss prtp prtr prus prut pruu pspp pspr psps psrp psst psts pstu pups pupu pur- purp purr purs puru puss pust put- puts putt putu rpps rpts rrrr rrsp rsps rstp rsts rstu rtps rtss rttp rtts rupp rupt rurp rurs ruru russ rust rusu ruts rutt rutu spps sprs spsp spss spst sptr spts spur spus sput srps srpt srsp srtp srtr ssps sspt ssrs ssss sstp ssts stpp stps strs stru stss sttr stup stur stus stut sup- supp supr sups supt sur- surp surr surs surt suru sus- susp suss sust susu sutu suus tppp tppr tprs tptp tptr tput trpp trps trst trtr trus trut truu tsps tspt tssr tsst tsts tsup ttss tttt tups tupu turp turr turs turt turu tuss tust tuts tutt tutu u-rp uppp uppu upup urss ursu urts urup urur urus urut uspp usps ussr usss usst ussu ustp usts usus uttu uuuu