ddd dde ddf ddi ddp ddx de- ded dee def dei dep dex dfd dfe dff dfi dfp dfx di- did die dif dii dip dix dpd dpe dpf dpi dpp dxd dxi dxp dxx ed- edd ede edf edi edp edx eed eee eef eep eex ef- efd efe eff efi efp efx eid eie eif eii eip eix ep- epd epe epf epi epp epx ex- exd exe exi exp exx fdd fde fdf fdi fdp fdx fed fee fef fei fep fex ffd ffe fff ffi ffp ffx fid fie fif fii fip fix fpd fpe fpi fpp fpx fxe fxi fxp fxx i-d i-f idd ide idf idi idp idx ie- ied iee ief iei iep iex ifd ife iff ifi ifp ifx iid iie iif iii iip iix ipd ipe ipf ipi ipp ipx ixe ixi p-p pdd pde pdf pdi pdp pdx ped pee pef pei pep pex pfd pfe pff pfi pfp pfx pid pie pif pii pip pix ppd ppe ppf ppi ppp ppx pxe xde xdf xdi xed xee xep xex xfe xfx xie xii xix xpd xpe xpf xpp xxi xxp xxx