-er a-a a-b a-t aaa aab aad aae aak aao aar aat ab- aba abb abd abe abk abo abr abt ad- ada adb add ade adk ado adr adt aea aeb aed aee aek aeo aer aet aka akb akd ake akk ako akr aoa aob aod aoe aok aoo aor aot ar- ara arb ard are ark aro arr art at- ata atb atd ate ato atr att baa bab bad bae bak bao bar bat bba bbb bbd bbe bbk bbo bbr bbt bda bdb bdd bde bdk bdo bdr bdt be- bea beb bed bee bek beo ber bet bka bkb bke bkk bko bkr bkt boa bob bod boe bok boo bor bot bra brb brd bre brk bro brr brt bta btb btd bte btk bto btr btt daa dab dad dae dak dao dar dat dba dbb dbd dbe dbk dbo dbr dbt dda ddb ddd dde ddk ddo ddr ddt de- dea deb ded dee dek deo der det dka dkb dke dkk dko dkr dkt doa dob dod doe dok doo dor dot dra drb drd dre drk dro drr drt dta dtb dtd dte dtk dto dtr dtt eaa eab ead eae eak eao ear eat eba ebb ebd ebe ebk ebo ebr ebt ed- eda edb edd ede edk edo edr edt eea eeb eed eee eek eeo eer eet eka ekb ekd eke eko ekr ekt eo- eoa eob eod eoe eok eoo eor eot era erb erd ere erk ero err ert eta etb etd ete etk eto etr ett k-t ka- kaa kab kad kae kak kao kar kat kba kbb kbd kbe kbk kbo kbr kda kdb kde kdk kdo kdr kdt ke- kea keb ked kee kek keo ker ket kkb kke kkk kkr kkt koa kob kod koe kok koo kor kot kra krd krk kro krr krt kta ktb kte ktk kto ktr ktt oaa oab oad oae oak oao oar oat ob- oba obb obd obe obk obo obr obt oda odb odd ode odo odr odt oea oeb oed oee oeo oer oet oka okb okd oke okk oko okr oo- ooa oob ood ook ooo oor oot or- ora orb ord ore ork oro orr ort ot- ota otb otd ote otk oto otr ott ra- raa rab rad rae rak rao rar rat rba rbb rbd rbe rbk rbo rbr rbt rda rdb rdd rde rdo rdr rdt re- rea reb red ree rek reo rer ret rkb rke rkk rko rkt roa rob rod roe rok roo ror rot rra rrb rrd rrk rrr rrt rta rtb rtd rte rtk rto rtr rtt taa tab tad tae tak tao tar tat tba tbb tbd tbe tbk tbo tbr tbt tda tdb tdd tde tdk tdo tdr tdt te- tea teb ted tee tek teo ter tet tka tkb tke tkk tko tkr tkt to- toa tob tod toe tok too tor tot tra trb trd tre trk tro trr trt tta ttb ttd tte ttk tto ttr ttt