a-a a-b a-t aaa aab aae aak aao aat ab- aba abb abe abk abo abt aea aeb aee aek aeo aet aka akb ake akk ako aoa aob aoe aok aoo aot at- ata atb ate ato att baa bab bae bak bao bat bba bbb bbe bbk bbo bbt be- bea beb bee bek beo bet bka bkb bke bkk bko bkt boa bob boe bok boo bot bta btb bte btk bto btt eaa eab eae eak eao eat eba ebb ebe ebk ebo ebt eea eeb eee eek eeo eet eka ekb eke eko ekt eo- eoa eob eoe eok eoo eot eta etb ete etk eto ett k-t ka- kaa kab kae kak kao kat kba kbb kbe kbk kbo ke- kea keb kee kek keo ket kkb kke kkk kkt koa kob koe kok koo kot kta ktb kte ktk kto ktt oaa oab oae oak oao oat ob- oba obb obe obk obo obt oea oeb oee oeo oet oka okb oke okk oko oo- ooa oob ook ooo oot ot- ota otb ote otk oto ott taa tab tae tak tao tat tba tbb tbe tbk tbo tbt te- tea teb tee tek teo tet tka tkb tke tkk tko tkt to- toa tob toe tok too tot tta ttb tte ttk tto ttt