a-a a-b a-t a-z aaa aab aar aat aau aax aaz ab- aba abb abr abt abu abx abz ar- ara arb arr art aru arx arz at- ata atb atr att atu atx atz au- aua aub aur aut aux auz ax- axa axr axt axx az- aza azb azt azu azx azz b-u baa bab bar bat bau bax baz bba bbb bbr bbt bbu bbx bra brb brr brt bru brx brz bta btb btr btt btu btx btz bua bub bur but buu bux buz bxb bxx bza bzr bzu bzz ra- raa rab rar rat rau rax raz rba rbb rbr rbt rbu rbx rra rrb rrr rrt rru rta rtb rtr rtt rtu rtx rtz rua rub rur rut ruu rux ruz rxr rza rzb t-x taa tab tar tat tau tax taz tba tbb tbr tbt tbu tbz tra trb trr trt tru trx trz tta ttb ttr ttt ttu ttx tua tub tur tut tuu tux tuz txt txu tza tzu ua- uaa uab uar uat uau uaz uba ubb ubr ubt ubu ubx ur- ura urb urr urt uru urx urz uta utb utr utt utu utx utz uua uur uut uuu uxb uxr uxt uxu uza uzb uzu xaa xar xat xau xbr xbx xrt xrx xtr xtx xxx zaa zab zar zat zax zaz zbb zbr zbt zta ztr zub zur zut zuz zxx zzr zzt zzx zzz