a-a a-b aaa aab aae aam aax ab- aba abb abe abm abx aea aeb aee aem aex ama amb ame amm amx ax- axa axe axm axx baa bab bae bam bax bba bbb bbe bbm bbx be- bea beb bee bem bex bma bmb bme bmm bmx bxb bxm bxx eaa eab eae eam eax eba ebb ebe ebm ebx eea eeb eee eem eex em- ema emb eme emm emx ex- exa exe exx maa mab mae mam max mba mbb mbe mbm mbx mea meb mee mem mex mma mmb mme mmm mmx mxa xaa xam xbe xbx xee xem xex xma xmm xmx xxx