a-a a-b aaa aab aam aar aax aay ab- aba abb abm abr abx aby ama amb amm amr amx amy ar- ara arb arm arr arx ary ax- axa axm axr axx ay- aya ayr ayx baa bab bam bar bax bay bba bbb bbm bbr bbx bby bma bmb bmm bmr bmx bra brb brm brr brx bry bxb bxm bxx by- bya bym byr m-r maa mab mam mar max may mba mbb mbm mbr mbx mma mmb mmm mmr mmx mra mrb mrm mrr mrx mry mxa mxr my- mya myb mym myr myx ra- raa rab ram rar rax ray rba rbb rbm rbr rbx rma rmb rmm rmr rmx rra rrb rrm rrr rxr ry- rya rym ryr ryy xaa xam xar xbr xbx xma xmm xmr xmx xrx xry xxx xxy xyr xyy yaa yab yam yar yax yay ybm ybr yby yma ymm yra yxa yxy yyb yyy