-er bbb bbe bbr bbs bbt be- beb bee ber bes bet bev brb bre brr brs brt brv bsb bse bsr bss bst bsv btb bte btr bts btt btv bvb bve bvr bvs bvt bvv ebb ebe ebr ebs ebt ebv eeb eee eer ees eet eev erb ere err ers ert erv es- esb ese esr ess est esv etb ete etr ets ett etv evb eve evr evs evt evv rbb rbe rbr rbs rbt re- reb ree rer res ret rev rrb rrr rrs rrt rsb rse rsr rss rst rsv rtb rte rtr rts rtt rtv rvb rve rvr rvs rvt rvv sbb sbe sbr sbs sbt sbv se- seb see ser ses set sev sr- srb sre srr srs srt srv ss- ssb sse ssr sss sst ssv stb ste str sts stt stv svb sve svr svs svt svv tbb tbe tbr tbs tbt tbv te- teb tee ter tes tet tev trb tre trr trs trt trv tsb tse tsr tss tst tsv ttb tte ttr tts ttt ttv tvb tve tvr tvs tvt v-e vbr vbs vbv veb vee ver ves vet vrb vre vrr vrs vrt vsb vse vsr vss vst vsv vtb vte vtr vts vtt vtv vvb vvr vvs vvt vvv

bbbb bbbs bbeb bbet bebb bebe beeb beer bees beet bere berr bers bert bes- bese bess best bete bets bett betv bevs breb bree brer bres bret brev brrr brrs brsb brsr brst bseb bsee bser bses bset bsse bsts bstv btrt btss bttb ebbr ebbs eber ebes eeee eees eers eese eete eets erbb erbe ereb erer eres eret erev erre errs erse erst erts erve esbs esee eser eses eset esse esst este estr ests estv etbr etee eter etes etre ette ever eves evet evre evrs evst rbbb rbbr rbbs rbss rbst rebb rebe rebs reeb rees reet reev rere rers rert rese ress rest rete retr rets rett reve revs rrrr rsee rsre rsts rtee rtes rtss rtts rtve rver s-vt sbbs sber sbse sbst se-e se-s se-t sebe sebs sebt seeb seer sees seet serb sere serr sers sert serv sese sess sest set- sete sets sett seve sreb sres srtr srtv ssbr ssee sses sset ssrs sssb ssss sstb ssts st-v stbs stee ster stes stet stev stre strs stss sttr stvs svet svtr tbbs tbrb tbst teer tees teet teev ter- tere terr ters tese tess test tete tetr tets tett tre- tree tres tret trev trst trte trtr trvs tses tset tsse tssr tsst tsts ttbb tter ttss tttt tvbs tver tves tvrr tvss tvtv veer vees veet ver- verb vere vers vert vese vess vest vete vetr vets veve vret vrse vsee vses vsse vtes vtrs vver vvsb vvvv

-tree bbbee bbser be-er beber bebes beebe beebs beers beest beete beets beeve berbe beres beret berre berse berte berts besee beset besse beste bests betee beter betes betre betrs bett- bette betts bever beves breer brees breet brere brers brese bress brest brets brett breve brrrr bt-sv btr-t e-vsb ebber ebbet ebers ebert eeeee eevee eever eeves erbbe erber erebs erere erest erets ereve erres erses erste ersts erte erter ertes esere esser esses essse estee ester estes estet estre etest etete etree etres etter ettes evere everr evers evert evese evest evete evets evett eveve evres rebbe reber rebet rebts reere reese reest reeve rere- reree reres reret resee reses reset resse reste restr rests retee reter retes rette retts rever reves revet revvs rtrev rvers sebbe sebes sebet seebe seere seers seese seest seete seetv seeve serbs serer seres seret serre serse serss sert- serte serts sertv serve servt seser seses sesse seste setee seter setse sette setts sever sssrb sssss steer stees steet stere sterr sters stert stete stets steve strbe streb stree stret strrs strve svete tbtbt teber tebet teebs teers teese teest teets teres teret terre terrs terse tert- terve tesse teste tests teter tetes tetr- tette teves tevet treer trees treet trere tres- trese tress trest trete trets trett treve trevs tsebe tsere tsets tsvet ttest ttttt tvset veber vebre veere veers veeve verbs vereb veres verre verse verss verst verte verts verve veses vesre vesse veste vests vette vever vrees

b-tree bbbbbb bbsers beebee beebes beerse beerst beeste beeter beever beeves berbee berber berbes bereet berere berest berets berrer berres berret bersee berset bertes bertre besbes besbre besert besets besser besses besset bester betere betete bettee better bettes bevers brebes breere breese breest breres bresse breste brests brette bretts brever breves brevet bs-tbs bverse ebbers ebbert ebbest ebbets eberts eebree erbree eretes errest errett erster ervest essebt essert essess esssse estees esters esteve estree estres estter esttes esvres everse everte everts r-tree rebbes rebets reeser reeses reests reever reeves rerees resees resets reseve rester restes restte reteer retees reteet retere retest retree retret retter reverb revere revers revert revess revest revets revver sebete sebree sebseb see-er seesee serere serers serest serre- serres serret servee server serves servet sesser sesses sester sestet sestre setees seters settee setter severe severs sevre sevres steber steere steers steeve stere- sterer steres sterre sterte sterve stever steves street stress strete sverre t-test t-tree tbtest teebee teerts teests teetee teeter teevee terese terete terets terrer terres terret terser terset terter tertre tesser tesses testee tester testes tetete tetter tevere trebes treete treets tresse tretee tretes trette treves trevet tsetse tsvett ttests tvsets vebret veerer veerse veress verree verrer verres verret verser verses verset versse verste versts vertes vertre verver verves vervet vesess vesses vestee vester vestes vetere vetter vettes vevers vsb-tv vttest vvvvvv

b-trees bbbbbbb beetree beevers berbere berbers beretts berrett bertree beserve bestbet besteer bestest betrese betrest betters beverse breeses bresser brettes brevets errevet ersters es-tset esterre esteves estrees estreet estrete evebest everest everett rebetes reserve resever ressett resseve resters restest reteere reterre retests retrete rettert reverbs reveree reverer reveres reverse reverts revests revette seeress seesees seester servees servers servest sesters sestets sestett sesvete