-er a-a a-b a-t a-z aaa aab aae aar aat aaz ab- aba abb abe abr abt abz aea aeb aee aer aet aez ar- ara arb are arr art arz at- ata atb ate atr att atz az- aza azb aze azt azz baa bab bae bar bat baz bba bbb bbe bbr bbt be- bea beb bee ber bet bez bra brb bre brr brt brz bta btb bte btr btt btz bza bze bzr bzz eaa eab eae ear eat eaz eba ebb ebe ebr ebt eea eeb eee eer eet era erb ere err ert erz eta etb ete etr ett etz eze ezr ezz ra- raa rab rae rar rat raz rba rbb rbe rbr rbt re- rea reb ree rer ret rez rra rrb rrr rrt rta rtb rte rtr rtt rtz rza rzb rze taa tab tae tar tat taz tba tbb tbe tbr tbt tbz te- tea teb tee ter tet tez tra trb tre trr trt trz tta ttb tte ttr ttt tza tze zaa zab zar zat zaz zbb zbr zbt zea zeb zee zer zet zez zta zte ztr zzr zzt zzz