-er a-a a-b a-c aaa aab aac aae aag aan aar aas ab- aba abb abc abe abg abn abr abs ac- aca acb acc ace acg acn acr acs aea aeb aec aee aeg aen aer aes ag- aga agb agc age agg agn agr ags an- ana anb anc ane ang ann anr ans ar- ara arb arc are arg arn arr ars as- asa asb asc ase asg asn asr ass baa bab bac bae bag ban bar bas bba bbb bbc bbe bbg bbn bbr bbs bca bcb bcc bce bcg bcn bcr bcs be- bea beb bec bee beg ben ber bes bga bgb bgc bge bgg bgn bgr bgs bna bnb bnc bne bng bnn bnr bns bra brb bre brg brn brr brs bsa bsb bsc bse bsg bsn bsr bss c-- caa cab cac cae cag can car cas cba cbb cbc cbe cbg cbn cbr cbs cca ccb ccc cce ccg ccn ccr ccs ce- cea ceb cec cee ceg cen cer ces cga cgb cgc cge cgg cgn cgr cgs cn- cna cnb cnc cne cng cnn cnr cns cra crb crc cre crg crn crr crs csa csb csc cse csg csn csr css eaa eab eac eae eag ean ear eas eba ebb ebc ebe ebg ebn ebr ebs ec- eca ecb ecc ece ecg ecn ecr ecs eea eeb eec eee eeg een eer ees ega egb egc ege egg egn egr egs en- ena enb enc ene eng enn enr ens era erb erc ere erg ern err ers es- esa esb esc ese esg esn esr ess gaa gab gac gae gag gan gar gas gba gbc gbe gbg gbn gbr gbs gca gcb gcc gce gcg gcn gcr gcs ge- gea geb gec gee geg gen ger ges gga ggb ggc ggg ggn ggr ggs gna gnb gnc gne gnn gnr gns gra grb grc gre grg grn grr grs gsa gsb gsc gse gsg gsn gsr gss naa nab nac nae nag nan nar nas nba nbb nbc nbe nbg nbn nbr nbs nca ncb ncc nce ncg ncn ncr ncs ne- nea neb nec nee neg nen ner nes nga ngb ngc nge ngg ngn ngs nna nnb nnc nne nng nnn nns nra nrb nrc nre nrg nrn nrr nrs nsa nsb nsc nse nsg nsn nsr nss ra- raa rab rac rae rag ran rar ras rba rbb rbc rbe rbg rbn rbr rbs rca rcb rcc rce rcg rcn rcr rcs re- rea reb rec ree reg ren rer res rga rgb rgc rge rgg rgn rgr rgs rna rnb rnc rng rnn rnr rns rra rrb rrc rrg rrn rrr rrs rsa rsb rsc rse rsg rsn rsr rss saa sab sac sae sag san sar sas sba sbb sbc sbe sbg sbn sbr sbs sca scb scc sce scg scn scr scs se- sea seb sec see seg sen ser ses sga sgb sgc sge sgg sgn sgr sgs sna snb snc sne sng snn snr sns sr- sra srb src sre srg srn srr srs ss- ssa ssb ssc sse ssg ssn ssr sss