-er a-a a-b a-t aaa aab aad aae aao aar aas aat ab- aba abb abd abe abo abr abs abt ad- ada adb add ade ado adr ads adt aea aeb aed aee aeo aer aes aet aoa aob aod aoe aoo aor aos aot ar- ara arb ard are aro arr ars art as- asa asb asd ase aso asr ass ast at- ata atb atd ate ato atr ats att baa bab bad bae bao bar bas bat bba bbb bbd bbe bbo bbr bbs bbt bda bdb bdd bde bdo bdr bds bdt be- bea beb bed bee beo ber bes bet boa bob bod boe boo bor bos bot bra brb brd bre bro brr brs brt bsa bsb bsd bse bso bsr bss bst bta btb btd bte bto btr bts btt daa dab dad dae dao dar das dat dba dbb dbd dbe dbo dbr dbs dbt dda ddb ddd dde ddo ddr dds ddt de- dea deb ded dee deo der des det doa dob dod doe doo dor dos dot dra drb drd dre dro drr drs drt dsa dsb dsd dse dso dsr dss dst dta dtb dtd dte dto dtr dts dtt eaa eab ead eae eao ear eas eat eba ebb ebd ebe ebo ebr ebs ebt ed- eda edb edd ede edo edr eds edt eea eeb eed eee eeo eer ees eet eo- eoa eob eod eoe eoo eor eos eot era erb erd ere ero err ers ert es- esa esb esd ese eso esr ess est eta etb etd ete eto etr ets ett oaa oab oad oae oao oar oas oat ob- oba obb obd obe obo obr obs obt oda odb odd ode odo odr ods odt oea oeb oed oee oeo oer oes oet oo- ooa oob ood ooo oor oos oot or- ora orb ord ore oro orr ors ort os- osa osb osd ose oso osr oss ost ot- ota otb otd ote oto otr ots ott ra- raa rab rad rae rao rar ras rat rba rbb rbd rbe rbo rbr rbs rbt rda rdb rdd rde rdo rdr rds rdt re- rea reb red ree reo rer res ret roa rob rod roe roo ror ros rot rra rrb rrd rrr rrs rrt rsa rsb rsd rse rso rsr rss rst rta rtb rtd rte rto rtr rts rtt saa sab sad sae sao sar sas sat sba sbb sbd sbe sbo sbr sbs sbt sda sdb sdd sde sdo sdr sds sdt se- sea seb sed see seo ser ses set soa sob sod soe soo sor sos sot sr- sra srb srd sre sro srr srs srt ss- ssa ssb ssd sse sso ssr sss sst sta stb std ste sto str sts stt taa tab tad tae tao tar tas tat tba tbb tbd tbe tbo tbr tbs tbt tda tdb tdd tde tdo tdr tds tdt te- tea teb ted tee teo ter tes tet to- toa tob tod toe too tor tos tot tra trb trd tre tro trr trs trt tsa tsb tsd tse tso tsr tss tst tta ttb ttd tte tto ttr tts ttt