-er a-a a-b a-t aaa aab aad aae aao aar aat ab- aba abb abd abe abo abr abt ad- ada adb add ade ado adr adt aea aeb aed aee aeo aer aet aoa aob aod aoe aoo aor aot ar- ara arb ard are aro arr art at- ata atb atd ate ato atr att baa bab bad bae bao bar bat bba bbb bbd bbe bbo bbr bbt bda bdb bdd bde bdo bdr bdt be- bea beb bed bee beo ber bet boa bob bod boe boo bor bot bra brb brd bre bro brr brt bta btb btd bte bto btr btt daa dab dad dae dao dar dat dba dbb dbd dbe dbo dbr dbt dda ddb ddd dde ddo ddr ddt de- dea deb ded dee deo der det doa dob dod doe doo dor dot dra drb drd dre dro drr drt dta dtb dtd dte dto dtr dtt eaa eab ead eae eao ear eat eba ebb ebd ebe ebo ebr ebt ed- eda edb edd ede edo edr edt eea eeb eed eee eeo eer eet eo- eoa eob eod eoe eoo eor eot era erb erd ere ero err ert eta etb etd ete eto etr ett oaa oab oad oae oao oar oat ob- oba obb obd obe obo obr obt oda odb odd ode odo odr odt oea oeb oed oee oeo oer oet oo- ooa oob ood ooo oor oot or- ora orb ord ore oro orr ort ot- ota otb otd ote oto otr ott ra- raa rab rad rae rao rar rat rba rbb rbd rbe rbo rbr rbt rda rdb rdd rde rdo rdr rdt re- rea reb red ree reo rer ret roa rob rod roe roo ror rot rra rrb rrd rrr rrt rta rtb rtd rte rto rtr rtt taa tab tad tae tao tar tat tba tbb tbd tbe tbo tbr tbt tda tdb tdd tde tdo tdr tdt te- tea teb ted tee teo ter tet to- toa tob tod toe too tor tot tra trb trd tre tro trr trt tta ttb ttd tte tto ttr ttt