-er c-- ccc ccd cce cco ccr cct cdc cdd cde cdo cdr cdt ce- cec ced cee ceo cer cet co- coc cod coe coo cor cot crc crd cre cro crr crt ctc ctd cte cto ctr ctt dcc dcd dce dco dcr dct ddc ddd dde ddo ddr ddt de- dec ded dee deo der det doc dod doe doo dor dot drc drd dre dro drr drt dtc dtd dte dto dtr dtt ec- ecc ecd ece eco ecr ect ed- edc edd ede edo edr edt eec eed eee eeo eer eet eo- eoc eod eoe eoo eor eot erc erd ere ero err ert etc etd ete eto etr ett oc- occ ocd oco ocr oct odc odd ode odo odr odt oec oed oee oeo oer oet oo- ooc ood ooo oor oot or- orc ord ore oro orr ort ot- otc otd ote oto otr ott rcc rcd rce rco rcr rct rdc rdd rde rdo rdr rdt re- rec red ree reo rer ret roc rod roe roo ror rot rrc rrd rrr rrt rtc rtd rte rto rtr rtt tcc tcd tce tco tcr tct tdc tdd tde tdo tdr tdt te- tec ted tee teo ter tet to- toc tod toe too tor tot trc trd tre tro trr trt ttc ttd tte tto ttr ttt