c-- ccc ccd cce cco ccx cdc cdd cde cdo cdx ce- cec ced cee ceo cex co- coc cod coe coo cox cxc cxo cxx dcc dcd dce dco dcx ddc ddd dde ddo ddx de- dec ded dee deo dex doc dod doe doo dox dxc dxd dxo dxx ec- ecc ecd ece eco ecx ed- edc edd ede edo edx eec eed eee eeo eex eo- eoc eod eoe eoo ex- exc exd exe exo exx oc- occ ocd oco ocx odc odd ode odo oec oed oee oeo oex oo- ooc ood ooo oox ox- oxc oxo oxx xcd xcx xdc xde xed xee xex xoc xod xoo xox xxo xxx