-er a-a a-b a-c aaa aab aac aae aag aar aas ab- aba abb abc abe abg abr abs ac- aca acb acc ace acg acr acs aea aeb aec aee aeg aer aes ag- aga agb agc age agg agr ags ar- ara arb arc are arg arr ars as- asa asb asc ase asg asr ass baa bab bac bae bag bar bas bba bbb bbc bbe bbg bbr bbs bca bcb bcc bce bcg bcr bcs be- bea beb bec bee beg ber bes bga bgb bgc bge bgg bgr bgs bra brb bre brg brr brs bsa bsb bsc bse bsg bsr bss c-- caa cab cac cae cag car cas cba cbb cbc cbe cbg cbr cbs cca ccb ccc cce ccg ccr ccs ce- cea ceb cec cee ceg cer ces cga cgb cgc cge cgg cgr cgs cra crb crc cre crg crr crs csa csb csc cse csg csr css eaa eab eac eae eag ear eas eba ebb ebc ebe ebg ebr ebs ec- eca ecb ecc ece ecg ecr ecs eea eeb eec eee eeg eer ees ega egb egc ege egg egr egs era erb erc ere erg err ers es- esa esb esc ese esg esr ess gaa gab gac gae gag gar gas gba gbc gbe gbg gbr gbs gca gcb gcc gce gcg gcr gcs ge- gea geb gec gee geg ger ges gga ggb ggc ggg ggr ggs gra grb grc gre grg grr grs gsa gsb gsc gse gsg gsr gss ra- raa rab rac rae rag rar ras rba rbb rbc rbe rbg rbr rbs rca rcb rcc rce rcg rcr rcs re- rea reb rec ree reg rer res rga rgb rgc rge rgg rgr rgs rra rrb rrc rrg rrr rrs rsa rsb rsc rse rsg rsr rss saa sab sac sae sag sar sas sba sbb sbc sbe sbg sbr sbs sca scb scc sce scg scr scs se- sea seb sec see seg ser ses sga sgb sgc sge sgg sgr sgs sr- sra srb src sre srg srr srs ss- ssa ssb ssc sse ssg ssr sss