a-a a-b a-i aaa aab aai aan aax ab- aba abb abi abn abx ai- aia aib aii ain aix an- ana anb ani ann anx ax- axa axi axn axx baa bab bai ban bax bba bbb bbi bbn bbx bi- bia bib bii bin bix bna bnb bni bnn bnx bxb bxi bxn bxx ia- iaa iab iai ian iba ibb ibi ibn ibx iia iib iii iin iix in- ina inb ini inn inx ixi ixn n-i naa nab nai nan nax nba nbb nbi nbn nbx nia nib nii nin nix nna nnb nni nnn xaa xan xbx xia xii xin xix xna xxi xxx