a-a a-b a-t aaa aab aae aak aat ab- aba abb abe abk abt aea aeb aee aek aet aka akb ake akk at- ata atb ate att baa bab bae bak bat bba bbb bbe bbk bbt be- bea beb bee bek bet bka bkb bke bkk bkt bta btb bte btk btt eaa eab eae eak eat eba ebb ebe ebk ebt eea eeb eee eek eet eka ekb eke ekt eta etb ete etk ett k-t ka- kaa kab kae kak kat kba kbb kbe kbk ke- kea keb kee kek ket kkb kke kkk kkt kta ktb kte ktk ktt taa tab tae tak tat tba tbb tbe tbk tbt te- tea teb tee tek tet tka tkb tke tkk tkt tta ttb tte ttk ttt