a-a aaa aad aae aaf aax ad- ada add ade adf adx aea aed aee aef aex af- afa afd afe aff afx ax- axa axe axx daa dad dae daf dax dda ddd dde ddf ddx de- dea ded dee def dex dfa dfd dfe dff dfx dxd dxx eaa ead eae eaf eax ed- eda edd ede edf edx eea eed eee eef eex ef- efa efd efe eff efx ex- exa exd exe exx faa fad fae faf fax fda fdd fde fdf fdx fea fed fee fef fex ffa ffd ffe fff ffx fxe fxx xaa xad xaf xda xde xdf xed xee xex xfa xfe xfx xxx