-er bbb bbc bbe bbg bbk bbo bbr bbs bbt bcb bcc bce bcg bck bco bcr bcs bct be- beb bec bee beg bek beo ber bes bet bgb bgc bge bgg bgk bgo bgr bgs bgt bkb bkc bke bkg bkk bko bkr bks bkt bob boc boe bog bok boo bor bos bot brb bre brg brk bro brr brs brt bsb bsc bse bsg bsk bso bsr bss bst btb btc bte btg btk bto btr bts btt c-- cbb cbc cbe cbg cbk cbo cbr cbs cbt ccb ccc cce ccg cck cco ccr ccs cct ce- ceb cec cee ceg cek ceo cer ces cet cgb cgc cge cgg cgo cgr cgs cgt ckb ckc cko cks ckt co- cob coc coe cog cok coo cor cos cot crb crc cre crg crk cro crr crs crt csb csc cse csg csk cso csr css cst ctb ctc cte ctg ctk cto ctr cts ctt ebb ebc ebe ebg ebk ebo ebr ebs ebt ec- ecb ecc ece ecg eck eco ecr ecs ect eeb eec eee eeg eek eeo eer ees eet egb egc ege egg ego egr egs egt ekb ekc eke ekg eko ekr eks ekt eo- eob eoc eoe eog eok eoo eor eos eot erb erc ere erg erk ero err ers ert es- esb esc ese esg esk eso esr ess est etb etc ete etg etk eto etr ets ett gbc gbe gbg gbk gbo gbr gbs gbt gcb gcc gce gcg gck gco gcr gcs gct ge- geb gec gee geg gek geo ger ges get ggb ggc ggg ggo ggr ggs ggt gkb gko gks gkt gob goc goe gog gok goo gor gos got grb grc gre grg grk gro grr grs grt gsb gsc gse gsg gsk gso gsr gss gst gtb gtc gte gtg gtk gto gtr gts gtt k-t kbb kbc kbe kbk kbo kbr kbs kcb kcc kce kcg kck kcr kcs kct ke- keb kec kee keg kek keo ker kes ket kgb kgc kgo kgs kkb kkc kke kkk kkr kks kkt kob koc koe kog kok koo kor kos kot krc krg krk kro krr krs krt ksb ksc kse ksg ksk kso ksr kss kst ktb ktc kte ktg ktk kto ktr kts ktt ob- obb obc obe obg obk obo obr obs obt oc- ocb occ ocg ock oco ocr ocs oct oeb oec oee oeg oeo oer oes oet ogc oge ogg ogo ogs ogt okb okc oke okg okk oko okr oks oo- oob ooc oog ook ooo oor oos oot or- orb orc ore org ork oro orr ors ort os- osb osc ose osg osk oso osr oss ost ot- otb otc ote otg otk oto otr ots ott rbb rbc rbe rbg rbk rbo rbr rbs rbt rcb rcc rce rcg rco rcr rcs rct re- reb rec ree reg rek reo rer res ret rgb rgc rge rgg rgk rgo rgr rgs rgt rkb rkc rke rkg rkk rko rks rkt rob roc roe rog rok roo ror ros rot rrb rrc rrg rrk rrr rrs rrt rsb rsc rse rsg rsk rso rsr rss rst rtb rtc rte rtg rtk rto rtr rts rtt sbb sbc sbe sbg sbk sbo sbr sbs sbt scb scc sce scg sck sco scr scs sct se- seb sec see seg sek seo ser ses set sgb sgc sge sgg sgk sgo sgr sgs sgt sk- skb skc ske skg skk sko skr sks skt sob soc soe sog sok soo sor sos sot sr- srb src sre srg srk sro srr srs srt ss- ssb ssc sse ssg ssk sso ssr sss sst stb stc ste stg stk sto str sts stt tbb tbc tbe tbg tbk tbo tbr tbs tbt tcb tcc tce tcg tck tco tcr tcs tct te- teb tec tee teg tek teo ter tes tet tgb tgc tge tgg tgk tgo tgr tgs tgt tkb tkc tke tkg tkk tko tkr tks tkt to- tob toc toe tog tok too tor tos tot trb trc tre trg trk tro trr trs trt tsb tsc tse tsg tsk tso tsr tss tst ttb ttc tte ttg ttk tto ttr tts ttt