-er b-u bbb bbc bbe bbk bbr bbt bbu bcb bcc bce bck bcr bct bcu be- beb bec bee bek ber bet beu bkb bkc bke bkk bkr bkt brb bre brk brr brt bru btb btc bte btk btr btt btu bub buc bue buk bur but buu c-- cbb cbc cbe cbk cbr cbt cbu ccb ccc cce cck ccr cct ccu ce- ceb cec cee cek cer cet ceu ckb ckc ckt crb crc cre crk crr crt cru ctb ctc cte ctk ctr ctt ctu cub cuc cue cuk cur cut cuu ebb ebc ebe ebk ebr ebt ebu ec- ecb ecc ece eck ecr ect ecu eeb eec eee eek eer eet ekb ekc eke ekr ekt eku erb erc ere erk err ert eru etb etc ete etk etr ett etu eu- eub euc eue eur eut k-t kbb kbc kbe kbk kbr kbu kcb kcc kce kck kcr kct kcu ke- keb kec kee kek ker ket kkb kkc kke kkk kkr kkt kku krc krk krr krt kru ktb ktc kte ktk ktr ktt ktu kub kuc kue kuk kur kut kuu rbb rbc rbe rbk rbr rbt rbu rcb rcc rce rcr rct rcu re- reb rec ree rek rer ret reu rkb rkc rke rkk rkt rku rrb rrc rrk rrr rrt rru rtb rtc rte rtk rtr rtt rtu rub ruc rue ruk rur rut ruu tbb tbc tbe tbk tbr tbt tbu tcb tcc tce tck tcr tct tcu te- teb tec tee tek ter tet teu tkb tkc tke tkk tkr tkt trb trc tre trk trr trt tru ttb ttc tte ttk ttr ttt ttu tub tuc tue tuk tur tut tuu ubb ubc ube ubk ubr ubt ubu ucb ucc uce uck ucr uct ucu ueb uec uee uer uet ukb ukc uke ukk ukr uku ur- urb urc ure urk urr urt uru utb utc ute utk utr utt utu uuc uue uur uut uuu

bbbb bbeb bbet bbrc bcbc bccc bcec bcer bcet bcru bctc bcuc bebb bebe beck becu beeb beek beer beet beke berc bere berk berr bert beru betc bete bett betu beuk beur brcb brce breb brec bree brek brer bret brkb brrr brtc bruc brue brut btcc btec btek btrc btrt bttb bubb bube bubu bucc buce buck bucu buer bueu buke bukk buku bur- burb bure burk burr burt buru but- bute butt cbbc cbcc cbce cbcr cbct cbcu cbec cbee cber cbet cbkr cbre cbrt cbtc ccbc cccb cccc cccu ccee ccrc ccre ccrt cctb cctc cctt ccuc ccut cebu cec- cece cect ceeb ceec ceke cer- cerc cere cert cet- cete ckbc ckbe ckck cker ckrc cktb crbc crbu crcc crce crcr cre- creb crec cree cret creu crkc crrt crtc crub crue cruk crut ctec ctrc cub- cubb cube cucc cuce cuck cuek cuer cuk- cuke curb cure curr curt cut- cutc cute cutt ebbc ebbr ebcc eber ebru ebur ecbc ecbe eccb eccc ecce ecct ecrc ecrr ecru ect- ectc eeee eeke eerc eetc eete eetu ekeb ekek eker eket ekur erbb erbe ercc erce ereb erec erer eret erke errc erre ertu erub eruc erur etbc etbr etcc etec etee eter etre ette ettu eubc euer eur- eurc eure eurt kbbb kbbc kbbe kbbk kbbr kbbt kbbu kbcb kbce kbck kbcr kbct kbcu kbeb kbec kbee kbek kber kbet kbkb kbkk kbkr kbrb kbrc kbre kbrk kbrt kbru kbtb kbtc kbte kbtk kbtr kbtt kbub kbuc kbue kbuk kbur kbut kbuu kcbc kcbk kcbr kcbu kccb kccc kcck kccr kcct kccu kceb kcec kcee kcet kceu kckc kckk kckr kcrc kcrr kcrt kcru kctb kctc kcte kctu kcub kcue kcuk kebb kebc kebe kebr kebt kebu keck kecr keek keer keet kekb kekc keke keku ker- kerb kerc kere kerk kerr kert keru ket- ketc kete ketk ketr kett ketu keur kkbb kkbe kkbr kkbt kkcb kkck kkcr kkct kkkk kkrb kkrc kkre kkrk kkrr kkrt kktc kktk kktu kkut kkuu krbb krbe krbk krbr krbt krcb krcc krce krcu kreb krec kree krek kret kreu krkc krke krkk krkr krku krrb krrc krre krrk krrr krrt krtc krtk krtr kruc krue kruk krur ktbb ktbc ktbr ktbt ktbu ktcc ktce ktck ktcr ktec ktee ktek ktkb ktkc ktke ktkk ktkr ktkt ktku ktrb ktrc ktre ktrk ktrr ktrt ktru kttc kttk kttr kttt kttu ktub ktuc kubb kubc kube kubr kubu kucb kucc kuce kucr kuek kueu kuke kukk kuku kurb kure kurk kurr kurt kuru kute kutr kutt kutu kuub kuuk kuur kuuu rbbb rbbr rcbc rccb rccc rcet rctc rebb rebe rebk rebu recc rece reck recr rect recu reeb reek reet reke rekt rere rert reru rete retr rett reue reuk reut reuu rrrr rtcc rtce rtee rubb rube rubu ruce ruck ruct ruer ruet ruke rukk ruku rurc rure ruru rute rutt rutu tbcb tbcc tbce tbrb tccc tccu tctc tebu teck tecr tect teec teek teer teet teke ter- terc tere terk terr teru tete tetr tett tetu teuk teut trcc tre- trec tree trek tret treu trtc trte trtr trub truc true truk trut truu ttbb tter tttt tubb tube tubr tubu tucc tuck tuer tuet tuke turb turc ture turk turr turt turu tute tutt tutu ubbe ubek uber ubet ucbc ucrc ucut ukcc ukek ukeu ukrc ukur urbe ure- uret urke urre urte uruk urur urut utec uter uttu uuuu

-tree b-r-k bbbee be-er bebek beber becke becue becut beebe beeke beete beeut beker bekke berbe berck bercu berec berek beret berk- berke berre berru berte betee beter betke betre bett- bette beuer beure beute brebu brece breck breek breer breet breke brere brett breu- brrrr bruce bruck bruer bruet bruke brute btc-e btr-t bubbe buber bucek bucet bucku bucur buker buket bukk- burck burcu burek buret burke burru burte burtt buruc buruk burut butec buter butke butte butut c-tec ccccc ccett cebec ceber ceere cerbu cerc- cerce cerec cerer ceret cerke