a-a a-b a-t a-z aaa aab aan aar aat aaz ab- aba abb abn abr abt abz an- ana anb ann anr ant anz ar- ara arb arn arr art arz at- ata atb atn atr att atz az- aza azb azn azt azz baa bab ban bar bat baz bba bbb bbn bbr bbt bna bnb bnn bnr bnt bnz bra brb brn brr brt brz bta btb btn btr btt btz bza bzn bzr bzz naa nab nan nar nat naz nba nbb nbn nbr nbt nna nnb nnn nnt nnz nra nrb nrn nrr nrt nrz nta ntb ntn ntr ntt ntz nzb nzz ra- raa rab ran rar rat raz rba rbb rbn rbr rbt rna rnb rnn rnr rnt rnz rra rrb rrn rrr rrt rta rtb rtn rtr rtt rtz rza rzb taa tab tan tar tat taz tba tbb tbn tbr tbt tbz tna tnb tnn tnr tnt tnz tra trb trn trr trt trz tta ttb ttn ttr ttt tza zaa zab zan zar zat zaz zbb zbr zbt znn zta ztr zzr zzt zzz