c-- ccc cce ccs cct ccx ce- cec cee ces cet cex csc cse css cst csx ctc cte cts ctt ctx cxc cxs cxt cxx ec- ecc ece ecs ect ecx eec eee ees eet eex es- esc ese ess est esx etc ete ets ett etx ex- exc exe exs ext exx scc sce scs sct scx se- sec see ses set sex ss- ssc sse sss sst ssx stc ste sts stt stx sxc sxs sxt t-x tcc tce tcs tct tcx te- tec tee tes tet tex tsc tse tss tst tsx ttc tte tts ttt ttx txe txs txt xcx xee xes xet xex xsc xss xst xtc xts xtx xxx