-er bbb bbe bbg bbo bbr bbs bbt be- beb bee beg beo ber bes bet bgb bge bgg bgo bgr bgs bgt bob boe bog boo bor bos bot brb bre brg bro brr brs brt bsb bse bsg bso bsr bss bst btb bte btg bto btr bts btt ebb ebe ebg ebo ebr ebs ebt eeb eee eeg eeo eer ees eet egb ege egg ego egr egs egt eo- eob eoe eog eoo eor eos eot erb ere erg ero err ers ert es- esb ese esg eso esr ess est etb ete etg eto etr ets ett gbe gbg gbo gbr gbs gbt ge- geb gee geg geo ger ges get ggb ggg ggo ggr ggs ggt gob goe gog goo gor gos got grb gre grg gro grr grs grt gsb gse gsg gso gsr gss gst gtb gte gtg gto gtr gts gtt ob- obb obe obg obo obr obs obt oeb oee oeg oeo oer oes oet oge ogg ogo ogs ogt oo- oob oog ooo oor oos oot or- orb ore org oro orr ors ort os- osb ose osg oso osr oss ost ot- otb ote otg oto otr ots ott rbb rbe rbg rbo rbr rbs rbt re- reb ree reg reo rer res ret rgb rge rgg rgo rgr rgs rgt rob roe rog roo ror ros rot rrb rrg rrr rrs rrt rsb rse rsg rso rsr rss rst rtb rte rtg rto rtr rts rtt sbb sbe sbg sbo sbr sbs sbt se- seb see seg seo ser ses set sgb sge sgg sgo sgr sgs sgt sob soe sog soo sor sos sot sr- srb sre srg sro srr srs srt ss- ssb sse ssg sso ssr sss sst stb ste stg sto str sts stt tbb tbe tbg tbo tbr tbs tbt te- teb tee teg teo ter tes tet tgb tge tgg tgo tgr tgs tgt to- tob toe tog too tor tos tot trb tre trg tro trr trs trt tsb tse tsg tso tsr tss tst ttb tte ttg tto ttr tts ttt