a-a a-b a-c a-t aaa aab aac aae aat ab- aba abb abc abe abt ac- aca acb acc ace act aea aeb aec aee aet at- ata atb atc ate att baa bab bac bae bat bba bbb bbc bbe bbt bca bcb bcc bce bct be- bea beb bec bee bet bta btb btc bte btt c-- caa cab cac cae cat cba cbb cbc cbe cbt cca ccb ccc cce cct ce- cea ceb cec cee cet cta ctb ctc cte ctt eaa eab eac eae eat eba ebb ebc ebe ebt ec- eca ecb ecc ece ect eea eeb eec eee eet eta etb etc ete ett taa tab tac tae tat tba tbb tbc tbe tbt tca tcb tcc tce tct te- tea teb tec tee tet tta ttb ttc tte ttt