-er a-a a-c aaa aac aae aag aak aap aar ac- aca acc ace acg ack acp acr aea aec aee aeg aek aep aer ag- aga agc age agg agk agp agr aka akc ake akg akk akp akr ap- apa apc ape apg apk app apr ar- ara arc are arg ark arp arr c-- caa cac cae cag cak cap car cca ccc cce ccg cck ccp ccr ce- cea cec cee ceg cek cep cer cga cgc cge cgg cgp cgr cka ckc cpa cpc cpe cpg cpk cpp cpr cra crc cre crg crk crp crr eaa eac eae eag eak eap ear ec- eca ecc ece ecg eck ecr eea eec eee eeg eek eep eer ega egc ege egg egp egr eka ekc eke ekg ekp ekr ep- epa epc epe epg epp epr era erc ere erg erk erp err g-p gaa gac gae gag gak gap gar gca gcc gce gcg gck gcp gcr ge- gea gec gee geg gek gep ger gga ggc ggg ggp ggr gka gkp gpa gpc gpe gpg gpk gpp gpr gra grc gre grg grk grp grr ka- kaa kac kae kag kak kap kar kca kcc kce kcg kck kcp kcr ke- kea kec kee keg kek kep ker kga kgc kgp kkc kke kkk kkp kkr kpa kpc kpe kpk kpp kpr kra krc krg krk krp krr p-p paa pac pae pag pak pap par pca pcc pce pcg pck pcp pcr pea pec pee peg pek pep per pga pgc pge pgg pgk pgp pgr pka pkc pke pkg pkp pkr ppa ppc ppe ppg ppk ppp ppr pra prc pre prg prk prp prr ra- raa rac rae rag rak rap rar rca rcc rce rcg rcp rcr re- rea rec ree reg rek rep rer rga rgc rge rgg rgk rgp rgr rkc rke rkg rkk rkp rpa rpc rpe rpg rpk rpp rpr rra rrc rrg rrk rrp rrr