-er a-a a-c aaa aac aae aag aao aar aas ac- aca acc ace acg aco acr acs aea aec aee aeg aeo aer aes ag- aga agc age agg ago agr ags aoa aoc aoe aog aoo aor aos ar- ara arc are arg aro arr ars as- asa asc ase asg aso asr ass c-- caa cac cae cag cao car cas cca ccc cce ccg cco ccr ccs ce- cea cec cee ceg ceo cer ces cga cgc cge cgg cgo cgr cgs co- coa coc coe cog coo cor cos cra crc cre crg cro crr crs csa csc cse csg cso csr css eaa eac eae eag eao ear eas ec- eca ecc ece ecg eco ecr ecs eea eec eee eeg eeo eer ees ega egc ege egg ego egr egs eo- eoa eoc eoe eog eoo eor eos era erc ere erg ero err ers es- esa esc ese esg eso esr ess gaa gac gae gag gao gar gas gca gcc gce gcg gco gcr gcs ge- gea gec gee geg geo ger ges gga ggc ggg ggo ggr ggs goa goc goe gog goo gor gos gra grc gre grg gro grr grs gsa gsc gse gsg gso gsr gss oaa oac oae oag oao oar oas oc- oca occ ocg oco ocr ocs oea oec oee oeg oeo oer oes oga ogc oge ogg ogo ogs oo- ooa ooc oog ooo oor oos or- ora orc ore org oro orr ors os- osa osc ose osg oso osr oss ra- raa rac rae rag rao rar ras rca rcc rce rcg rco rcr rcs re- rea rec ree reg reo rer res rga rgc rge rgg rgo rgr rgs roa roc roe rog roo ror ros rra rrc rrg rrr rrs rsa rsc rse rsg rso rsr rss saa sac sae sag sao sar sas sca scc sce scg sco scr scs se- sea sec see seg seo ser ses sga sgc sge sgg sgo sgr sgs soa soc soe sog soo sor sos sr- sra src sre srg sro srr srs ss- ssa ssc sse ssg sso ssr sss