-er b-u bbb bbc bbe bbm bbo bbr bbu bcb bcc bce bcm bco bcr bcu be- beb bec bee bem beo ber beu bmb bmc bme bmm bmo bmr bmu bob boc boe bom boo bor bou brb bre brm bro brr bru bub buc bue bum buo bur buu c-- cbb cbc cbe cbm cbo cbr cbu ccb ccc cce ccm cco ccr ccu ce- ceb cec cee cem ceo cer ceu cmb cmc cme cmm cmo cmr cmu co- cob coc coe com coo cor cou crb crc cre crm cro crr cru cub cuc cue cum cuo cur cuu ebb ebc ebe ebm ebo ebr ebu ec- ecb ecc ece ecm eco ecr ecu eeb eec eee eem eeo eer em- emb emc eme emm emo emr emu eo- eob eoc eoe eom eoo eor eou erb erc ere erm ero err eru eu- eub euc eue eur m-o m-r mbb mbc mbe mbm mbo mbr mbu mc- mcb mcc mce mcm mco mcr mcu meb mec mee mem meo mer meu mmb mmc mme mmm mmo mmr mmu mob moc moe mom moo mor mou mrb mrc mre mrm mro mrr mru mub muc mue mum mur muu ob- obb obc obe obm obo obr obu oc- ocb occ ocm oco ocr ocu oeb oec oee oem oeo oer om- omb omc ome omm omo omr omu oo- oob ooc oom ooo oor or- orb orc ore orm oro orr oru ou- ouc oue oum ouo our rbb rbc rbe rbm rbo rbr rbu rcb rcc rce rcm rco rcr rcu re- reb rec ree rem reo rer reu rmb rmc rme rmm rmo rmr rob roc roe rom roo ror rou rrb rrc rrm rrr rru rub ruc rue rum ruo rur ruu ubb ubc ube ubo ubr ubu ucb ucc uce ucm uco ucr ucu ueb uec uee uem uer um- umb umc ume umm umo umr umu uob uoc uoe uom uoo uor ur- urb urc ure urm uro urr uru uuc uue uum uur uuu