bbbb bbeb bbrc bcbc bccc bcec bcer bcru bcuc bebb bebe beck becu beeb beek beer beke berc bere berk berr beru beuk beur brcb brce breb brec bree brek brer brkb brrr bruc brue bubb bube bubu bucc buce buck bucu buer bueu buke bukk buku bur- burb bure burk burr buru cbbc cbcc cbce cbcr cbcu cbec cbee cber cbkr cbre ccbc cccb cccc cccu ccee ccrc ccre ccuc cebu cec- cece ceeb ceec ceke cer- cerc cere ckbc ckbe ckck cker ckrc crbc crbu crcc crce crcr cre- creb crec cree creu crkc crub crue cruk cub- cubb cube cucc cuce cuck cuek cuer cuk- cuke curb cure curr ebbc ebbr ebcc eber ebru ebur ecbc ecbe eccb eccc ecce ecrc ecrr ecru eeee eeke eerc ekeb ekek eker ekur erbb erbe ercc erce ereb erec erer erke errc erre erub eruc erur eubc euer eur- eurc eure kbbb kbbc kbbe kbbk kbbr kbbu kbcb kbce kbck kbcr kbcu kbeb kbec kbee kbek kber kbkb kbkk kbkr kbrb kbrc kbre kbrk kbru kbub kbuc kbue kbuk kbur kbuu kcbc kcbk kcbr kcbu kccb kccc kcck kccr kccu kceb kcec kcee kceu kckc kckk kckr kcrc kcrr kcru kcub kcue kcuk kebb kebc kebe kebr kebu keck kecr keek keer kekb kekc keke keku ker- kerb kerc kere kerk kerr keru keur kkbb kkbe kkbr kkcb kkck kkcr kkkk kkrb kkrc kkre kkrk kkrr kkuu krbb krbe krbk krbr krcb krcc krce krcu kreb krec kree krek kreu krkc krke krkk krkr krku krrb krrc krre krrk krrr kruc krue kruk krur kubb kubc kube kubr kubu kucb kucc kuce kucr kuek kueu kuke kukk kuku kurb kure kurk kurr kuru kuub kuuk kuur kuuu rbbb rbbr rcbc rccb rccc rebb rebe rebk rebu recc rece reck recr recu reeb reek reke rere reru reue reuk reuu rrrr rubb rube rubu ruce ruck ruer ruke rukk ruku rurc rure ruru ubbe ubek uber ucbc ucrc ukcc ukek ukeu ukrc ukur urbe ure- urke urre uruk urur uuuu