-er b-u bbb bbc bbe bbk bbm bbr bbu bcb bcc bce bck bcm bcr bcu be- beb bec bee bek bem ber beu bkb bkc bke bkk bkm bkr bmb bmc bme bmk bmm bmr bmu brb bre brk brm brr bru bub buc bue buk bum bur buu c-- cbb cbc cbe cbk cbm cbr cbu ccb ccc cce cck ccm ccr ccu ce- ceb cec cee cek cem cer ceu ckb ckc ckm cmb cmc cme cmk cmm cmr cmu crb crc cre crk crm crr cru cub cuc cue cuk cum cur cuu ebb ebc ebe ebk ebm ebr ebu ec- ecb ecc ece eck ecm ecr ecu eeb eec eee eek eem eer ekb ekc eke ekr eku em- emb emc eme emk emm emr emu erb erc ere erk erm err eru eu- eub euc eue eur kbb kbc kbe kbk kbm kbr kbu kcb kcc kce kck kcm kcr kcu ke- keb kec kee kek kem ker kkb kkc kke kkk kkm kkr kku kmb kmc kme kmk kmm kmu krc krk krr kru kub kuc kue kuk kum kur kuu m-r mbb mbc mbe mbk mbm mbr mbu mc- mcb mcc mce mck mcm mcr mcu meb mec mee mek mem mer meu mkb mkc mke mkk mkm mkr mku mmb mmc mme mmk mmm mmr mmu mrb mrc mre mrk mrm mrr mru mub muc mue muk mum mur muu rbb rbc rbe rbk rbm rbr rbu rcb rcc rce rcm rcr rcu re- reb rec ree rek rem rer reu rkb rkc rke rkk rkm rku rmb rmc rme rmm rmr rrb rrc rrk rrm rrr rru rub ruc rue ruk rum rur ruu ubb ubc ube ubk ubr ubu ucb ucc uce uck ucm ucr ucu ueb uec uee uem uer ukb ukc uke ukk ukr uku um- umb umc ume umm umr umu ur- urb urc ure urk urm urr uru uuc uue uum uur uuu