c-- ccc cce ccf cco ccs ce- cec cee cef ceo ces cfc cfe cff cfo cfs co- coc coe cof coo cos csc cse csf cso css ec- ecc ece ecf eco ecs eec eee eef eeo ees ef- efc efe eff efo efs eo- eoc eoe eof eoo eos es- esc ese esf eso ess fcc fce fcf fco fcs fec fee fef feo fes ffc ffe fff ffo ffs foc foe fof foo fos fsc fse fsf fso fss oc- occ ocf oco ocs oec oee oef oeo oes of- ofc ofe off ofo ofs oo- ooc oof ooo oos os- osc ose osf oso oss scc sce scf sco scs se- sec see sef seo ses sfc sfe sff sfo sfs soc soe sof soo sos ss- ssc sse ssf sso sss