-er a-a a-c aaa aac aae aag aam aar ac- aca acc ace acg acm acr aea aec aee aeg aem aer ag- aga agc age agg agm agr ama amc ame amg amm amr ar- ara arc are arg arm arr c-- caa cac cae cag cam car cca ccc cce ccg ccm ccr ce- cea cec cee ceg cem cer cga cgc cge cgg cgm cgr cma cmc cme cmg cmm cmr cra crc cre crg crm crr eaa eac eae eag eam ear ec- eca ecc ece ecg ecm ecr eea eec eee eeg eem eer ega egc ege egg egm egr em- ema emc eme emg emm emr era erc ere erg erm err gaa gac gae gag gam gar gca gcc gce gcg gcm gcr ge- gea gec gee geg gem ger gga ggc ggg ggm ggr gma gmc gme gmg gmm gmr gra grc gre grg grm grr m-r maa mac mae mag mam mar mc- mca mcc mce mcg mcm mcr mea mec mee meg mem mer mga mgc mge mgm mgr mma mmc mme mmg mmm mmr mra mrc mre mrg mrm mrr ra- raa rac rae rag ram rar rca rcc rce rcg rcm rcr re- rea rec ree reg rem rer rga rgc rge rgg rgr rma rmc rme rmg rmm rmr rra rrc rrg rrm rrr