-er c-- ccc cce ccg cco ccr ccs cct ce- cec cee ceg ceo cer ces cet cgc cge cgg cgo cgr cgs cgt co- coc coe cog coo cor cos cot crc cre crg cro crr crs crt csc cse csg cso csr css cst ctc cte ctg cto ctr cts ctt ec- ecc ece ecg eco ecr ecs ect eec eee eeg eeo eer ees eet egc ege egg ego egr egs egt eo- eoc eoe eog eoo eor eos eot erc ere erg ero err ers ert es- esc ese esg eso esr ess est etc ete etg eto etr ets ett gcc gce gcg gco gcr gcs gct ge- gec gee geg geo ger ges get ggc ggg ggo ggr ggs ggt goc goe gog goo gor gos got grc gre grg gro grr grs grt gsc gse gsg gso gsr gss gst gtc gte gtg gto gtr gts gtt oc- occ ocg oco ocr ocs oct oec oee oeg oeo oer oes oet ogc oge ogg ogo ogs ogt oo- ooc oog ooo oor oos oot or- orc ore org oro orr ors ort os- osc ose osg oso osr oss ost ot- otc ote otg oto otr ots ott rcc rce rcg rco rcr rcs rct re- rec ree reg reo rer res ret rgc rge rgg rgo rgr rgs rgt roc roe rog roo ror ros rot rrc rrg rrr rrs rrt rsc rse rsg rso rsr rss rst rtc rte rtg rto rtr rts rtt scc sce scg sco scr scs sct se- sec see seg seo ser ses set sgc sge sgg sgo sgr sgs sgt soc soe sog soo sor sos sot sr- src sre srg sro srr srs srt ss- ssc sse ssg sso ssr sss sst stc ste stg sto str sts stt tcc tce tcg tco tcr tcs tct te- tec tee teg teo ter tes tet tgc tge tgg tgo tgr tgs tgt to- toc toe tog too tor tos tot trc tre trg tro trr trs trt tsc tse tsg tso tsr tss tst ttc tte ttg tto ttr tts ttt