bbbb bbeb bbrc bcbc bccc bcec bcer bebb bebe beck beeb beek beer beke berc bere berk berr brcb brce breb brec bree brek brer brkb brrr cbbc cbcc cbce cbcr cbec cbee cber cbkr cbre ccbc cccb cccc ccee ccrc ccre cec- cece ceeb ceec ceke cer- cerc cere ckbc ckbe ckck cker ckrc crbc crcc crce crcr cre- creb crec cree crkc ebbc ebbr ebcc eber ecbc ecbe eccb eccc ecce ecrc ecrr eeee eeke eerc ekeb ekek eker erbb erbe ercc erce ereb erec erer erke errc erre kbbb kbbc kbbe kbbk kbbr kbcb kbce kbck kbcr kbeb kbec kbee kbek kber kbkb kbkk kbkr kbrb kbrc kbre kbrk kcbc kcbk kcbr kccb kccc kcck kccr kceb kcec kcee kckc kckk kckr kcrc kcrr kebb kebc kebe kebr keck kecr keek keer kekb kekc keke ker- kerb kerc kere kerk kerr kkbb kkbe kkbr kkcb kkck kkcr kkkk kkrb kkrc kkre kkrk kkrr krbb krbe krbk krbr krcb krcc krce kreb krec kree krek krkc krke krkk krkr krrb krrc krre krrk krrr rbbb rbbr rcbc rccb rccc rebb rebe rebk recc rece reck recr reeb reek reke rere rrrr