-er a-a a-b a-c a-t aaa aab aac aad aae aao aar aas aat ab- aba abb abc abd abe abo abr abs abt ac- aca acb acc acd ace aco acr acs act ad- ada adb adc add ade ado adr ads adt aea aeb aec aed aee aeo aer aes aet aoa aob aoc aod aoe aoo aor aos aot ar- ara arb arc ard are aro arr ars art as- asa asb asc asd ase aso asr ass ast at- ata atb atc atd ate ato atr ats att baa bab bac bad bae bao bar bas bat bba bbb bbc bbd bbe bbo bbr bbs bbt bca bcb bcc bcd bce bco bcr bcs bct bda bdb bdc bdd bde bdo bdr bds bdt be- bea beb bec bed bee beo ber bes bet boa bob boc bod boe boo bor bos bot bra brb brd bre bro brr brs brt bsa bsb bsc bsd bse bso bsr bss bst bta btb btc btd bte bto btr bts btt c-- caa cab cac cad cae cao car cas cat cba cbb cbc cbd cbe cbo cbr cbs cbt cca ccb ccc ccd cce cco ccr ccs cct cda cdb cdc cdd cde cdo cdr cds cdt ce- cea ceb cec ced cee ceo cer ces cet co- coa cob coc cod coe coo cor cos cot cra crb crc crd cre cro crr crs crt csa csb csc csd cse cso csr css cst cta ctb ctc ctd cte cto ctr cts ctt daa dab dac dad dae dao dar das dat dba dbb dbc dbd dbe dbo dbr dbs dbt dca dcb dcc dcd dce dco dcr dcs dct dda ddb ddc ddd dde ddo ddr dds ddt de- dea deb dec ded dee deo der des det doa dob doc dod doe doo dor dos dot dra drb drc drd dre dro drr drs drt dsa dsb dsc dsd dse dso dsr dss dst dta dtb dtc dtd dte dto dtr dts dtt eaa eab eac ead eae eao ear eas eat eba ebb ebc ebd ebe ebo ebr ebs ebt ec- eca ecb ecc ecd ece eco ecr ecs ect ed- eda edb edc edd ede edo edr eds edt eea eeb eec eed eee eeo eer ees eet eo- eoa eob eoc eod eoe eoo eor eos eot era erb erc erd ere ero err ers ert es- esa esb esc esd ese eso esr ess est eta etb etc etd ete eto etr ets ett oaa oab oac oad oae oao oar oas oat ob- oba obb obc obd obe obo obr obs obt oc- oca ocb occ ocd oco ocr ocs oct oda odb odc odd ode odo odr ods odt oea oeb oec oed oee oeo oer oes oet oo- ooa oob ooc ood ooo oor oos oot or- ora orb orc ord ore oro orr ors ort os- osa osb osc osd ose oso osr oss ost ot- ota otb otc otd ote oto otr ots ott ra- raa rab rac rad rae rao rar ras rat rba rbb rbc rbd rbe rbo rbr rbs rbt rca rcb rcc rcd rce rco rcr rcs rct rda rdb rdc rdd rde rdo rdr rds rdt re- rea reb rec red ree reo rer res ret roa rob roc rod roe roo ror ros rot rra rrb rrc rrd rrr rrs rrt rsa rsb rsc rsd rse rso rsr rss rst rta rtb rtc rtd rte rto rtr rts rtt saa sab sac sad sae sao sar sas sat sba sbb sbc sbd sbe sbo sbr sbs sbt sca scb scc scd sce sco scr scs sct sda sdb sdc sdd sde sdo sdr sds sdt se- sea seb sec sed see seo ser ses set soa sob soc sod soe soo sor sos sot sr- sra srb src srd sre sro srr srs srt ss- ssa ssb ssc ssd sse sso ssr sss sst sta stb stc std ste sto str sts stt taa tab tac tad tae tao tar tas tat tba tbb tbc tbd tbe tbo tbr tbs tbt tca tcb tcc tcd tce tco tcr tcs tct tda tdb tdc tdd tde tdo tdr tds tdt te- tea teb tec ted tee teo ter tes tet to- toa tob toc tod toe too tor tos tot tra trb trc trd tre tro trr trs trt tsa tsb tsc tsd tse tso tsr tss tst tta ttb ttc ttd tte tto ttr tts ttt