-er c-- ccc cce ccr ccs cct ccx ce- cec cee cer ces cet cex crc cre crr crs crt crx csc cse csr css cst csx ctc cte ctr cts ctt ctx cxc cxr cxs cxt cxx ec- ecc ece ecr ecs ect ecx eec eee eer ees eet eex erc ere err ers ert es- esc ese esr ess est esx etc ete etr ets ett etx ex- exc exe exr exs ext exx rcc rce rcr rcs rct rcx re- rec ree rer res ret rex rrc rrr rrs rrt rsc rse rsr rss rst rsx rtc rte rtr rts rtt rtx rxr rxs scc sce scr scs sct scx se- sec see ser ses set sex sr- src sre srr srs srt srx ss- ssc sse ssr sss sst ssx stc ste str sts stt stx sxc sxs sxt t-x tcc tce tcr tcs tct tcx te- tec tee ter tes tet tex trc tre trr trs trt trx tsc tse tsr tss tst tsx ttc tte ttr tts ttt ttx txe txs txt xcr xcx xee xer xes xet xex xrc xrt xrx xsc xss xst xtc xtr xts xtx xxx