a-a a-b aaa aab aan aar aax aay ab- aba abb abn abr abx aby an- ana anb ann anr anx any ar- ara arb arn arr arx ary ax- axa axn axr axx ay- aya ayn ayr ayx baa bab ban bar bax bay bba bbb bbn bbr bbx bby bna bnb bnn bnr bnx bra brb brn brr brx bry bxb bxn bxx by- bya byn byr naa nab nan nar nax nay nba nbb nbn nbr nbx nna nnb nnn nra nrb nrn nrr nrx nry nya nyn nyx nyy ra- raa rab ran rar rax ray rba rbb rbn rbr rbx rna rnb rnn rnr rny rra rrb rrn rrr rxr ry- rya ryn ryr ryy xaa xan xar xbr xbx xna xrx xry xxx xxy xyr xyy yaa yab yan yar yax yay ybr yby yna ynn yny yra yrn yxa yxy yyb yyy