a-a a-b a-c a-t a-z aaa aab aac aae aat aaz ab- aba abb abc abe abt abz ac- aca acb acc ace act acz aea aeb aec aee aet aez at- ata atb atc ate att atz az- aza azb aze azt azz baa bab bac bae bat baz bba bbb bbc bbe bbt bca bcb bcc bce bct bcz be- bea beb bec bee bet bez bta btb btc bte btt btz bza bze bzz c-- caa cab cac cae cat caz cba cbb cbc cbe cbt cbz cca ccb ccc cce cct ccz ce- cea ceb cec cee cet cez cta ctb ctc cte ctt ctz cz- czc cze czt eaa eab eac eae eat eaz eba ebb ebc ebe ebt ec- eca ecb ecc ece ect eea eeb eec eee eet eta etb etc ete ett etz eze ezz taa tab tac tae tat taz tba tbb tbc tbe tbt tbz tca tcb tcc tce tct te- tea teb tec tee tet tez tta ttb ttc tte ttt tza tze zaa zab zac zat zaz zbb zbc zbt zce zea zeb zec zee zet zez zta zte zzt zzz