a-a a-b a-t aaa aab aad aae aat ab- aba abb abd abe abt ad- ada adb add ade adt aea aeb aed aee aet at- ata atb atd ate att baa bab bad bae bat bba bbb bbd bbe bbt bda bdb bdd bde bdt be- bea beb bed bee bet bta btb btd bte btt daa dab dad dae dat dba dbb dbd dbe dbt dda ddb ddd dde ddt de- dea deb ded dee det dta dtb dtd dte dtt eaa eab ead eae eat eba ebb ebd ebe ebt ed- eda edb edd ede edt eea eeb eed eee eet eta etb etd ete ett taa tab tad tae tat tba tbb tbd tbe tbt tda tdb tdd tde tdt te- tea teb ted tee tet tta ttb ttd tte ttt