-er c-- ccc cce cco ccr ccs cct ccx ce- cec cee ceo cer ces cet cex co- coc coe coo cor cos cot cox crc cre cro crr crs crt crx csc cse cso csr css cst csx ctc cte cto ctr cts ctt ctx cxc cxo cxr cxs cxt cxx ec- ecc ece eco ecr ecs ect ecx eec eee eeo eer ees eet eex eo- eoc eoe eoo eor eos eot erc ere ero err ers ert es- esc ese eso esr ess est esx etc ete eto etr ets ett etx ex- exc exe exo exr exs ext exx oc- occ oco ocr ocs oct ocx oec oee oeo oer oes oet oex oo- ooc ooo oor oos oot oox or- orc ore oro orr ors ort orx os- osc ose oso osr oss ost osx ot- otc ote oto otr ots ott ox- oxc oxo oxt oxx rcc rce rco rcr rcs rct rcx re- rec ree reo rer res ret rex roc roe roo ror ros rot rox rrc rrr rrs rrt rsc rse rso rsr rss rst rsx rtc rte rto rtr rts rtt rtx rxr rxs scc sce sco scr scs sct scx se- sec see seo ser ses set sex soc soe soo sor sos sot sox sr- src sre sro srr srs srt srx ss- ssc sse sso ssr sss sst ssx stc ste sto str sts stt stx sxc sxs sxt t-x tcc tce tco tcr tcs tct tcx te- tec tee teo ter tes tet tex to- toc toe too tor tos tot tox trc tre tro trr trs trt trx tsc tse tso tsr tss tst tsx ttc tte tto ttr tts ttt ttx txe txs txt xcr xcx xee xer xes xet xex xoc xoo xor xos xot xox xrc xrt xrx xsc xss xst xtc xtr xts xtx xxo xxx