-er a-a a-b a-t aaa aab aad aae aaf aao aar aat aax ab- aba abb abd abe abf abo abr abt abx ad- ada adb add ade adf ado adr adt adx aea aeb aed aee aef aeo aer aet aex af- afa afb afd afe aff afo afr aft afx aoa aob aod aoe aof aoo aor aot aox ar- ara arb ard are arf aro arr art arx at- ata atb atd ate atf ato atr att atx ax- axa axe axo axr axt axx baa bab bad bae baf bao bar bat bax bba bbb bbd bbe bbf bbo bbr bbt bbx bda bdb bdd bde bdf bdo bdr bdt bdx be- bea beb bed bee bef beo ber bet bex bfa bfb bfd bfe bff bfo bfr bft bfx boa bob bod boe bof boo bor bot box bra brb brd bre brf bro brr brt brx bta btb btd bte btf bto btr btt btx bxb bxd bxo bxx daa dab dad dae daf dao dar dat dax dba dbb dbd dbe dbf dbo dbr dbt dbx dda ddb ddd dde ddf ddo ddr ddt ddx de- dea deb ded dee def deo der det dex dfa dfb dfd dfe dff dfo dfr dft dfx doa dob dod doe dof doo dor dot dox dra drb drd dre dro drr drt drx dta dtb dtd dte dtf dto dtr dtt dtx dxd dxo dxr dxt dxx eaa eab ead eae eaf eao ear eat eax eba ebb ebd ebe ebf ebo ebr ebt ebx ed- eda edb edd ede edf edo edr edt edx eea eeb eed eee eef eeo eer eet eex ef- efa efb efd efe eff efo efr eft efx eo- eoa eob eod eoe eof eoo eor eot era erb erd ere erf ero err ert eta etb etd ete etf eto etr ett etx ex- exa exd exe exo exr ext exx faa fab fad fae faf fao far fat fax fba fbb fbd fbe fbf fbo fbr fbt fbx fda fdb fdd fde fdf fdo fdr fdt fdx fea feb fed fee fef feo fer fet fex ffa ffd ffe fff ffo ffr fft ffx foa fob foe fof foo for fot fox fra frb frd fre frf fro frr frt fta ftb ftd fte ftf fto ftr ftt ftx fxe fxr fxt fxx oaa oab oad oae oaf oao oar oat oax ob- oba obb obd obe obf obo obr obt obx oda odb odd ode odf odo odr odt oea oeb oed oee oef oeo oer oet oex of- ofa ofb ofd ofe off ofo ofr oft ofx oo- ooa oob ood oof ooo oor oot oox or- ora orb ord ore orf oro orr ort orx ot- ota otb otd ote otf oto otr ott ox- oxa oxb oxf oxo oxt oxx ra- raa rab rad rae raf rao rar rat rax rba rbb rbd rbe rbf rbo rbr rbt rbx rda rdb rdd rde rdf rdo rdr rdt rdx re- rea reb red ree ref reo rer ret rex rfa rfb rfd rfe rff rfo rfr rft roa rob rod roe rof roo ror rot rox rra rrb rrd rrf rrr rrt rta rtb rtd rte rtf rto rtr rtt rtx rxr t-x taa tab tad tae taf tao tar tat tax tba tbb tbd tbe tbf tbo tbr tbt tda tdb tdd tde tdf tdo tdr tdt tdx te- tea teb ted tee tef teo ter tet tex tfa tfb tfd tfe tff tfo tfr tft tfx to- toa tob tod toe tof too tor tot tox tra trb trd tre trf tro trr trt trx tta ttb ttd tte ttf tto ttr ttt ttx txe txf txt xaa xad xaf xar xat xbe xbr xbx xda xdb xde xdf xdr xdt xed xee xer xet xex xfa xfe xft xfx xoa xod xof xoo xor xot xox xrd xrf xrt xrx xtf xtr xtx xxo xxx