bbbb bbbs bbpr bibb bibi bibs biis bipp bips bipu birb biri birr birs birt biru bis- bisp biss bist bisu bits bitt bitu bpsu bpti bris brit brrr brrs brsb brsr brst brup brus brut bspp bspr bsts bsup btbp btps btrt btss bttb btus bubb bubi bubs bubu buir buis buit buiu bups bur- burb buri burp burr burs burt buru busi buss bust busu but- buti buts butt buus ibis ibri ibss ibtb ibts ibus iiii iiis iiit iirs iisi iisp iisr iist iisu iitr iitt ippr ipri ipsi ipsp ipss ipts ipur ipus iput irbp iri- irip iris irps irri irrs irsp irti irtp irts irus isbt isis isit ispr isps isri isrp issi issp issr isss issu isti istp istr ists isup isus itbs itis itri itrs itsi itsp itsu itup itur iuiu iupp iuss iust pbrs pbsp pibb pibi piip pipi pipp pips piri pirr pirs piru pisi piss pist pisu piti pitr pits pitt pitu pius ppib pppp ppps ppru ppss ppts pptt ppur prbs pri- prii pris prps prri prrs prsi prss prti prtp prtr prus prut pruu psbr psbt psip psis pspi pspp pspr psps psrp psst psts pstu ptui pubs pubu puir puis puit puiu pupi pups pupu pur- purb puri purp purr purs puru pusi puss pust put- puti puts putt putu rbbb rbbr rbbs rbis rbsp rbss rbst rib- ribs ribu riis ripi ripp ripr rips ript riri rirs risi risp riss rist risu riti rits ritt ritu rius rpii rpps rpts rrrr rrsp rsbi rsis rspb rsps rstp rsts rstu rtps rtss rttp rtts rubb rubi rubp rubs rubu ruis ruit rupp rupt ruri rurp rurs ruru rusi russ rust rusu ruti ruts rutt rutu s-ib s-ii sbbs sbsi sbsp sbst sbus sibi sibs sibu siit sipi sipp sips sipt siri sirp sirr sirs sirt siru sisi siss sist sisu sit- siti sits sitt situ siui sius siut spib spip spir spis spit spps spri sprs spsp spss spst sptb sptr spts spui spur spus sput srib sris srps srpt srsp srtp srtr srub ssbr ssis ssit ssps sspt ssri ssrs sssb sssi ssss sstb sstp ssts stbs stib stip stir stis stit stpp stps stri strs stru stsi stss sttr stub stup stur stus stut sub- subb subi subs suir suis suit sup- supp supr sups supt sur- suri surp surr surs surt suru sus- susi susp suss sust susu suti sutu suus tbbs tbit tbrb tbsp tbst tbtp tibi tibs tibu tiit tiiu tip- tipi tipp tips tipt tipu tirb tiri tirr tirs tiru tisb tisi tiss tist titi titp tits titt titu tpir tppp tppr tprs tptp tptr tput tri- trib trip tris trit trpp trps trsi trst trtr trub trus trut truu tsis tsps tspt tssi tssr tsst tsts tsui tsup ttbb ttss tttt tubb tubr tubs tubu tuis tuit tuiu tupi tups tupu turb turi turp turr turs turt turu tusi tuss tust tuti tuts tutt tutu u-rp ubbi ubii ubir ubis ubit uipi uirr uist uits upis uppp uppu upri upsi upup urbi urbs urib uris uriu urri ursi urss ursu urts urup urur urus urut usbr usbs usip usis uspp usps ussb ussr usss usst ussu ustb usti ustp usts usui usus utis utri utti uttu uuri uusi uuuu