a-a a-b a-t a-z aaa aab aae aao aat aaz ab- aba abb abe abo abt abz aea aeb aee aeo aet aez aoa aob aoe aoo aot at- ata atb ate ato att atz az- aza azb aze azo azt azz baa bab bae bao bat baz bba bbb bbe bbo bbt be- bea beb bee beo bet bez boa bob boe boo bot boz bta btb bte bto btt btz bza bze bzo bzz eaa eab eae eao eat eaz eba ebb ebe ebo ebt eea eeb eee eeo eet eo- eoa eob eoe eoo eot eta etb ete eto ett etz eze ezo ezz oaa oab oae oao oat ob- oba obb obe obo obt oea oeb oee oeo oet oo- ooa oob ooo oot ot- ota otb ote oto ott otz oza oze ozo ozt ozz taa tab tae tao tat taz tba tbb tbe tbo tbt tbz te- tea teb tee teo tet tez to- toa tob toe too tot toz tta ttb tte tto ttt tza tze zaa zab zao zat zaz zbb zbt zea zeb zee zeo zet zez zo- zoa zob zoe zoo zot zta zte zzt zzz