c-- ccc ccd cce ccf cco ccs cdc cdd cde cdf cdo cds ce- cec ced cee cef ceo ces cfc cfd cfe cff cfo cfs co- coc cod coe cof coo cos csc csd cse csf cso css dcc dcd dce dcf dco dcs ddc ddd dde ddf ddo dds de- dec ded dee def deo des dfc dfd dfe dff dfo dfs doc dod doe dof doo dos dsc dsd dse dsf dso dss ec- ecc ecd ece ecf eco ecs ed- edc edd ede edf edo eds eec eed eee eef eeo ees ef- efc efd efe eff efo efs eo- eoc eod eoe eof eoo eos es- esc esd ese esf eso ess fcc fcd fce fcf fco fcs fdc fdd fde fdf fdo fds fec fed fee fef feo fes ffc ffd ffe fff ffo ffs foc foe fof foo fos fsc fsd fse fsf fso fss oc- occ ocd ocf oco ocs odc odd ode odf odo ods oec oed oee oef oeo oes of- ofc ofd ofe off ofo ofs oo- ooc ood oof ooo oos os- osc osd ose osf oso oss scc scd sce scf sco scs sdc sdd sde sdf sdo sds se- sec sed see sef seo ses sfc sfd sfe sff sfo sfs soc sod soe sof soo sos ss- ssc ssd sse ssf sso sss