-er b-u bbb bbc bbe bbk bbr bbs bbu bcb bcc bce bck bcr bcs bcu be- beb bec bee bek ber bes beu bkb bkc bke bkk bkr bks brb bre brk brr brs bru bsb bsc bse bsk bsr bss bsu bub buc bue buk bur bus buu c-- cbb cbc cbe cbk cbr cbs cbu ccb ccc cce cck ccr ccs ccu ce- ceb cec cee cek cer ces ceu ckb ckc cks crb crc cre crk crr crs cru csb csc cse csk csr css csu cub cuc cue cuk cur cus cuu ebb ebc ebe ebk ebr ebs ebu ec- ecb ecc ece eck ecr ecs ecu eeb eec eee eek eer ees ekb ekc eke ekr eks eku erb erc ere erk err ers eru es- esb esc ese esk esr ess esu eu- eub euc eue eur eus kbb kbc kbe kbk kbr kbs kbu kcb kcc kce kck kcr kcs kcu ke- keb kec kee kek ker kes kkb kkc kke kkk kkr kks kku krc krk krr krs kru ksb ksc kse ksk ksr kss ksu kub kuc kue kuk kur kus kuu rbb rbc rbe rbk rbr rbs rbu rcb rcc rce rcr rcs rcu re- reb rec ree rek rer res reu rkb rkc rke rkk rks rku rrb rrc rrk rrr rrs rru rsb rsc rse rsk rsr rss rsu rub ruc rue ruk rur rus ruu sbb sbc sbe sbk sbr sbs sbu scb scc sce sck scr scs scu se- seb sec see sek ser ses seu sk- skb skc ske skk skr sks sku sr- srb src sre srk srr srs ss- ssb ssc sse ssk ssr sss ssu sub suc sue suk sur sus suu ubb ubc ube ubk ubr ubs ubu ucb ucc uce uck ucr ucs ucu ueb uec uee uer ues ukb ukc uke ukk ukr uku ur- urb urc ure urk urr urs uru usb usc use usk usr uss usu uuc uue uur uus uuu

bbbb bbbs bbeb bbrc bcbc bcbs bccc bccs bcec bcer bces bcrs bcru bcsc bcss bcuc bebb bebe beck becs becu beeb beek beer bees beke beks berc bere berk berr bers beru bes- bese besk bess beuk beur brcb brce breb brec bree brek brer bres brkb brrr brrs brsb brsr bruc brue brus bscs bseb bsec bsee bser bses bssc bsse bubb bube bubs bubu bucc buce buck bucs bucu buer bueu buke bukk buku bur- burb bure burk burr burs buru busc buse busk buss busu buus cbbc cbbs cbcc cbce cbcr cbcs cbcu cbec cbee cber cbkr cbre cbsc cbse cbus ccbc cccb cccc cccs cccu ccee ccrc ccre ccrs ccss ccuc ccus cebs cebu cec- cece cecs ceeb ceec cees ceke cer- cerc cere cers cesc cese cesr cess ckbc ckbe ckck ckcs cker ckrc cksb crbc crbu crcc crce crcr cre- creb crec cree cres creu crkc crss crub crue cruk crus cscb cscc csce cscr cscs csec csee cser csks csrc csrs csse cssr csur csus cub- cubb cube cubs cucc cuce cuck cuek cuer cues cuk- cuke curb cure curr curs cusb cusk cuss cusu ebbc ebbr ebbs ebcc eber ebes ebru ebur ebus ecbc ecbe eccb eccc ecce eces ecks ecrc ecrr ecru ecsc ecse ecss ecsu ecus eecs eeee eees eeke eeks eerc eers eese eesk ekeb ekek eker ekes ekur erbb erbe ercc erce ereb erec erer eres erke erks errc erre errs erse erub eruc erur erus esbs escb esce escr escs escu esee esek eser eses eske esks esku esse essu esus eubc euer eur- eurc eure euse kbbb kbbc kbbe kbbk kbbr kbbs kbbu kbcb kbce kbck kbcr kbcs kbcu kbeb kbec kbee kbek kber kbes kbkb kbkk kbkr kbrb kbrc kbre kbrk kbru kbsb kbsk kbsr kbss kbsu kbub kbuc kbue kbuk kbur kbus kbuu kcbc kcbk kcbr kcbs kcbu kccb kccc kcck kccr kccu kceb kcec kcee kceu kckc kckk kckr kcrc kcrr kcrs kcru kcsb kcsc kcse kcsr kcss kcsu kcub kcue kcuk kebb kebc kebe kebr kebu keck kecr keek keer kees kekb kekc keke keks keku ker- kerb kerc kere kerk kerr kers keru kesb kesc kesk kesr kess keur keus kkbb kkbe kkbr kkbs kkcb kkck kkcr kkcs kkkk kkrb kkrc kkre kkrk kkrr kkrs kkse kksr kkss kksu kkus kkuu krbb krbe krbk krbr krcb krcc krce krcs krcu kreb krec kree krek kres kreu krkc krke krkk krkr krks krku krrb krrc krre krrk krrr krrs krsc krse krsk krsr krss krsu kruc krue kruk krur ksbc ksbr ksbs kscb ksce ksck kscr kscs kscu ksec ksee ksek kser kskb kske kskk kskr ksks ksku ksrb ksrr ksrs ksse kssr ksss kssu ksub ksue ksuu kubb kubc kube kubr kubs kubu kucb kucc kuce kucr kuek kues kueu kuke kukk kuks kuku kurb kure kurk kurr kurs kuru kusb kusc kusu kuub kuuk kuur kuuu rbbb rbbr rbbs rbss rcbc rccb rccc rccs rcsc rcss rebb rebe rebk rebs rebu recc rece reck recr recs recu reeb reek rees reke reks rere rers reru rese ress reue reuk reus reuu rkss rrrr rscc rscs rsee rsre rubb rube rubs rubu ruce ruck ruer rues ruke rukk ruku rurc rure rurs ruru ruse rusk russ rusu sbbs sbcc sbcs sber sbrk sbse sbus sccc scce sccs scec scee scer sck- scr- scrc scre scrs scsc scsr scsu scub scur se-c se-e se-k se-s se-u sebe sebs sec- secc sece seck secr secs secu seeb seec seek seer sees seeu seke sekk seku serb serc sere serk serr sers seru sesc sese sess seur skee sker skes skss skue skur srbc srcc sreb srec sres srub ssbr sscc ssce sscs ssec ssee sses ssrc ssrs sssb sssc ssss sub- subb subs suc- succ suck sucr sucs suee suer sues sueu suke suks suku sur- surc sure surr surs suru sus- suse susk suss susu suus ubbe ubek uber ucbc uces ucrc ucsb ucsc ucsu