a-a a-b a-c a-t aaa aab aac aae aao aat ab- aba abb abc abe abo abt ac- aca acb acc ace aco act aea aeb aec aee aeo aet aoa aob aoc aoe aoo aot at- ata atb atc ate ato att baa bab bac bae bao bat bba bbb bbc bbe bbo bbt bca bcb bcc bce bco bct be- bea beb bec bee beo bet boa bob boc boe boo bot bta btb btc bte bto btt c-- caa cab cac cae cao cat cba cbb cbc cbe cbo cbt cca ccb ccc cce cco cct ce- cea ceb cec cee ceo cet co- coa cob coc coe coo cot cta ctb ctc cte cto ctt eaa eab eac eae eao eat eba ebb ebc ebe ebo ebt ec- eca ecb ecc ece eco ect eea eeb eec eee eeo eet eo- eoa eob eoc eoe eoo eot eta etb etc ete eto ett oaa oab oac oae oao oat ob- oba obb obc obe obo obt oc- oca ocb occ oco oct oea oeb oec oee oeo oet oo- ooa oob ooc ooo oot ot- ota otb otc ote oto ott taa tab tac tae tao tat tba tbb tbc tbe tbo tbt tca tcb tcc tce tco tct te- tea teb tec tee teo tet to- toa tob toc toe too tot tta ttb ttc tte tto ttt