bbbb bbbs bbin bibb bibi bibs biin biis bin- bini binn bins bint binu birb biri birn birr birs birt biru bis- biss bist bisu bits bitt bitu bnib bnin bnrr bnss brin bris brit brns brrr brrs brsb brsr brst brun brus brut bsin bsns bsts btrt btss bttb btus bubb bubi bubs bubu buin buir buis buit buiu bunb buni bunn buns bunt bunu bur- burb buri burn burr burs burt buru busi buss bust busu but- buti buts butt buus ibis ibns ibri ibsn ibss ibtb ibts ibus iiii iiis iiit iirs iisi iisr iist iisu iitr iitt inis init inni innr inns innu inri inrs inss inst insu inti intn intr ints intu inui inun inus iri- irin iris irri irrs irti irts irun irus isbn isbt isin isis isit isnt isri issi issr isss issu isti istr ists isus itbs itin itis itri itrs itsi itsu itur iuiu iuss iust n-ii nbti nibi nibs niir niit niiu nini nins nirs nirt niru nisi niss nist nisu nitb niti nitr nits niur nnit nnnn nnss nntn nrts nsin nsis nsnr nssb nssr nsss nsts nstu nsub ntis ntnu ntru ntsb ntss ntsu nttr ntui nubi nubs nuin nuit nunn nuns nunt nuri nurn nurr nurs nurt nuru nusi nuss nust nusu nuts nutt nutu rbbb rbbr rbbs rbis rbss rbst rib- ribs ribu riin riis rinn riri rirs risi riss rist risu riti rits ritt ritu rius rnbr rnin rnnt rnut rrrr rrun rsbi rsis rsnn rsnr rsts rstu rtns rtss rtts rubb rubi rubs rubu ruin ruis ruit runi runn runs runt ruri rurs ruru rusi russ rust rusu ruti ruts rutt rutu ruun s-ib s-ii sbbs sbsi sbst sbtn sbus sibi sibs sibu siit sini sinn sins sint sinu siri sirr sirs sirt siru sisi siss sist sisu sit- siti sitn sits sitt situ siui sius siut snib snir snit snns snrs sntr snub snur snus srib sris srni srnn srtr srub ssbn ssbr ssin ssis ssit ssns ssri ssrs sssb sssi ssss sstb ssts stbs stib stir stis stit stnn stnr stns stri strn strs stru stsi stss sttr stub stun stur stus stut sub- subb subi subs suin suir suis suit sun- sunb suni sunn suns sunt sunu sur- suri surn surr surs surt suru sus- susi suss sust susu suti sutu suus tbbs tbit tbrb tbst tibi tibs tibu tiit tiiu tini tinn tins tint tinu tirb tiri tirr tirs tiru tisb tisi tiss tist titi tits titt titu tnts tnut tri- trib trin tris trit trsi trst trtr trub trun trus trut truu tsin tsis tssi tssr tsst tsts tsui tsun ttbb ttss tttt tubb tubr tubs tubu tuin tuis tuit tuiu tunb tuni tunn tuns tunu turb turi turn turr turs turt turu tusi tuss tust tuti tuts tutt tutu ubbi ubii ubir ubis ubit uint uirr uist uits uni- unii unin unir unis unit unni unns unrs uns- unst untb unts unus unut urbi urbs urib urin uris uriu urni urns urri ursi urss ursu urts urun urur urus urut usbr usbs usin usis usnr usnu ussb ussr usss usst ussu ustb usti usts usui usun usus utin utis utri utti uttu uuni uuri uusi uuuu