a-a a-b a-t aaa aab aae aan aao aat ab- aba abb abe abn abo abt aea aeb aee aen aeo aet an- ana anb ane ann ano ant aoa aob aoe aon aoo aot at- ata atb ate atn ato att baa bab bae ban bao bat bba bbb bbe bbn bbo bbt be- bea beb bee ben beo bet bna bnb bne bnn bno bnt boa bob boe bon boo bot bta btb bte btn bto btt eaa eab eae ean eao eat eba ebb ebe ebn ebo ebt eea eeb eee een eeo eet en- ena enb ene enn eno ent eo- eoa eob eoe eon eoo eot eta etb ete etn eto ett naa nab nae nan nao nat nba nbb nbe nbn nbo nbt ne- nea neb nee nen neo net nna nnb nne nnn nno nnt no- noa nob noe non noo not nta ntb nte ntn nto ntt oaa oab oae oan oao oat ob- oba obb obe obn obo obt oea oeb oee oen oeo oet on- ona onb one onn ono ont oo- ooa oob oon ooo oot ot- ota otb ote otn oto ott taa tab tae tan tao tat tba tbb tbe tbn tbo tbt te- tea teb tee ten teo tet tna tnb tne tnn tno tnt to- toa tob toe ton too tot tta ttb tte ttn tto ttt