a-a a-b a-t aaa aab aad aae aak aao aat ab- aba abb abd abe abk abo abt ad- ada adb add ade adk ado adt aea aeb aed aee aek aeo aet aka akb akd ake akk ako aoa aob aod aoe aok aoo aot at- ata atb atd ate ato att baa bab bad bae bak bao bat bba bbb bbd bbe bbk bbo bbt bda bdb bdd bde bdk bdo bdt be- bea beb bed bee bek beo bet bka bkb bke bkk bko bkt boa bob bod boe bok boo bot bta btb btd bte btk bto btt daa dab dad dae dak dao dat dba dbb dbd dbe dbk dbo dbt dda ddb ddd dde ddk ddo ddt de- dea deb ded dee dek deo det dka dkb dke dkk dko dkt doa dob dod doe dok doo dot dta dtb dtd dte dtk dto dtt eaa eab ead eae eak eao eat eba ebb ebd ebe ebk ebo ebt ed- eda edb edd ede edk edo edt eea eeb eed eee eek eeo eet eka ekb ekd eke eko ekt eo- eoa eob eod eoe eok eoo eot eta etb etd ete etk eto ett k-t ka- kaa kab kad kae kak kao kat kba kbb kbd kbe kbk kbo kda kdb kde kdk kdo kdt ke- kea keb ked kee kek keo ket kkb kke kkk kkt koa kob kod koe kok koo kot kta ktb kte ktk kto ktt oaa oab oad oae oak oao oat ob- oba obb obd obe obk obo obt oda odb odd ode odo odt oea oeb oed oee oeo oet oka okb okd oke okk oko oo- ooa oob ood ook ooo oot ot- ota otb otd ote otk oto ott taa tab tad tae tak tao tat tba tbb tbd tbe tbk tbo tbt tda tdb tdd tde tdk tdo tdt te- tea teb ted tee tek teo tet tka tkb tke tkk tko tkt to- toa tob tod toe tok too tot tta ttb ttd tte ttk tto ttt