c-- ccc ccd cce ccs ccx cdc cdd cde cds cdx ce- cec ced cee ces cex csc csd cse css csx cxc cxs cxx dcc dcd dce dcs dcx ddc ddd dde dds ddx de- dec ded dee des dex dsc dsd dse dss dsx dxc dxd dxs dxx ec- ecc ecd ece ecs ecx ed- edc edd ede eds edx eec eed eee ees eex es- esc esd ese ess esx ex- exc exd exe exs exx scc scd sce scs scx sdc sdd sde sds se- sec sed see ses sex ss- ssc ssd sse sss ssx sxc sxs xcd xcx xdc xde xds xed xee xes xex xsc xss xxx