-er a-a a-b a-t aaa aab aae aag aak aar aas aat ab- aba abb abe abg abk abr abs abt aea aeb aee aeg aek aer aes aet ag- aga agb age agg agk agr ags agt aka akb ake akg akk akr aks ar- ara arb are arg ark arr ars art as- asa asb ase asg ask asr ass ast at- ata atb ate atg atr ats att baa bab bae bag bak bar bas bat bba bbb bbe bbg bbk bbr bbs bbt be- bea beb bee beg bek ber bes bet bga bgb bge bgg bgk bgr bgs bgt bka bkb bke bkg bkk bkr bks bkt bra brb bre brg brk brr brs brt bsa bsb bse bsg bsk bsr bss bst bta btb bte btg btk btr bts btt eaa eab eae eag eak ear eas eat eba ebb ebe ebg ebk ebr ebs ebt eea eeb eee eeg eek eer ees eet ega egb ege egg egr egs egt eka ekb eke ekg ekr eks ekt era erb ere erg erk err ers ert es- esa esb ese esg esk esr ess est eta etb ete etg etk etr ets ett gaa gab gae gag gak gar gas gat gba gbe gbg gbk gbr gbs gbt ge- gea geb gee geg gek ger ges get gga ggb ggg ggr ggs ggt gka gkb gks gkt gra grb gre grg grk grr grs grt gsa gsb gse gsg gsk gsr gss gst gta gtb gte gtg gtk gtr gts gtt k-t ka- kaa kab kae kag kak kar kas kat kba kbb kbe kbk kbr kbs ke- kea keb kee keg kek ker kes ket kga kgb kgs kkb kke kkk kkr kks kkt kra krg krk krr krs krt ksa ksb kse ksg ksk ksr kss kst kta ktb kte ktg ktk ktr kts ktt ra- raa rab rae rag rak rar ras rat rba rbb rbe rbg rbk rbr rbs rbt re- rea reb ree reg rek rer res ret rga rgb rge rgg rgk rgr rgs rgt rkb rke rkg rkk rks rkt rra rrb rrg rrk rrr rrs rrt rsa rsb rse rsg rsk rsr rss rst rta rtb rte rtg rtk rtr rts rtt saa sab sae sag sak sar sas sat sba sbb sbe sbg sbk sbr sbs sbt se- sea seb see seg sek ser ses set sga sgb sge sgg sgk sgr sgs sgt sk- ska skb ske skg skk skr sks skt sr- sra srb sre srg srk srr srs srt ss- ssa ssb sse ssg ssk ssr sss sst sta stb ste stg stk str sts stt taa tab tae tag tak tar tas tat tba tbb tbe tbg tbk tbr tbs tbt te- tea teb tee teg tek ter tes tet tga tgb tge tgg tgk tgr tgs tgt tka tkb tke tkg tkk tkr tks tkt tra trb tre trg trk trr trs trt tsa tsb tse tsg tsk tsr tss tst tta ttb tte ttg ttk ttr tts ttt