-er a-a a-c aaa aac aae aag aao aap aar ac- aca acc ace acg aco acp acr aea aec aee aeg aeo aep aer ag- aga agc age agg ago agp agr aoa aoc aoe aog aoo aop aor ap- apa apc ape apg apo app apr ar- ara arc are arg aro arp arr c-- caa cac cae cag cao cap car cca ccc cce ccg cco ccp ccr ce- cea cec cee ceg ceo cep cer cga cgc cge cgg cgo cgp cgr co- coa coc coe cog coo cop cor cpa cpc cpe cpg cpo cpp cpr cra crc cre crg cro crp crr eaa eac eae eag eao eap ear ec- eca ecc ece ecg eco ecr eea eec eee eeg eeo eep eer ega egc ege egg ego egp egr eo- eoa eoc eoe eog eoo eop eor ep- epa epc epe epg epo epp epr era erc ere erg ero erp err g-p gaa gac gae gag gao gap gar gca gcc gce gcg gco gcp gcr ge- gea gec gee geg geo gep ger gga ggc ggg ggo ggp ggr goa goc goe gog goo gop gor gpa gpc gpe gpg gpo gpp gpr gra grc gre grg gro grp grr oaa oac oae oag oao oap oar oc- oca occ ocg oco ocp ocr oea oec oee oeg oeo oep oer oga ogc oge ogg ogo ogp oo- ooa ooc oog ooo oop oor op- opa opc ope opg opo opp opr or- ora orc ore org oro orp orr p-p paa pac pae pag pao pap par pca pcc pce pcg pco pcp pcr pea pec pee peg peo pep per pga pgc pge pgg pgo pgp pgr poa poc poe pog poo pop por ppa ppc ppe ppg ppo ppp ppr pra prc pre prg pro prp prr ra- raa rac rae rag rao rap rar rca rcc rce rcg rco rcp rcr re- rea rec ree reg reo rep rer rga rgc rge rgg rgo rgp rgr roa roc roe rog roo rop ror rpa rpc rpe rpg rpo rpp rpr rra rrc rrg rrp rrr