-er bbb bbc bbe bbm bbo bbr bbs bbx bcb bcc bce bcm bco bcr bcs bcx be- beb bec bee bem beo ber bes bex bmb bmc bme bmm bmo bmr bms bmx bob boc boe bom boo bor bos box brb bre brm bro brr brs brx bsb bsc bse bsm bso bsr bss bsx bxb bxm bxo bxx c-- cbb cbc cbe cbm cbo cbr cbs cbx ccb ccc cce ccm cco ccr ccs ccx ce- ceb cec cee cem ceo cer ces cex cmb cmc cme cmm cmo cmr cms cmx co- cob coc coe com coo cor cos cox crb crc cre crm cro crr crs crx csb csc cse csm cso csr css csx cxc cxo cxr cxs cxx ebb ebc ebe ebm ebo ebr ebs ebx ec- ecb ecc ece ecm eco ecr ecs ecx eeb eec eee eem eeo eer ees eex em- emb emc eme emm emo emr ems emx eo- eob eoc eoe eom eoo eor eos erb erc ere erm ero err ers es- esb esc ese esm eso esr ess esx ex- exc exe exo exr exs exx m-o m-r mbb mbc mbe mbm mbo mbr mbs mbx mc- mcb mcc mce mcm mco mcr mcs mcx meb mec mee mem meo mer mes mex mmb mmc mme mmm mmo mmr mms mmx mob moc moe mom moo mor mos mox mrb mrc mre mrm mro mrr mrs mrx msb msc mse msm mso msr mss msx mxc mxr mxs ob- obb obc obe obm obo obr obs obx oc- ocb occ ocm oco ocr ocs ocx oeb oec oee oem oeo oer oes oex om- omb omc ome omm omo omr oms omx oo- oob ooc oom ooo oor oos oox or- orb orc ore orm oro orr ors orx os- osb osc ose osm oso osr oss osx ox- oxb oxc oxo oxx rbb rbc rbe rbm rbo rbr rbs rbx rcb rcc rce rcm rco rcr rcs rcx re- reb rec ree rem reo rer res rex rmb rmc rme rmm rmo rmr rms rmx rob roc roe rom roo ror ros rox rrb rrc rrm rrr rrs rsb rsc rse rsm rso rsr rss rsx rxr rxs sbb sbc sbe sbm sbo sbr sbs sbx scb scc sce scm sco scr scs scx se- seb sec see sem seo ser ses sex smb smc sme smm smo smr sms smx sob soc soe som soo sor sos sox sr- srb src sre srm sro srr srs srx ss- ssb ssc sse ssm sso ssr sss ssx sxc sxm sxs xbc xbe xbr xbx xcb xcr xcx xee xem xer xes xex xmc xmm xmo xmr xms xmx xoc xom xoo xor xos xox xrc xrx xsb xsc xsm xss xxo xxx