-er c-- ccc ccd cce cck cco ccr cct cdc cdd cde cdk cdo cdr cdt ce- cec ced cee cek ceo cer cet ckc ckd cko ckt co- coc cod coe cok coo cor cot crc crd cre crk cro crr crt ctc ctd cte ctk cto ctr ctt dcc dcd dce dck dco dcr dct ddc ddd dde ddk ddo ddr ddt de- dec ded dee dek deo der det dkc dke dkk dko dkr dkt doc dod doe dok doo dor dot drc drd dre drk dro drr drt dtc dtd dte dtk dto dtr dtt ec- ecc ecd ece eck eco ecr ect ed- edc edd ede edk edo edr edt eec eed eee eek eeo eer eet ekc ekd eke eko ekr ekt eo- eoc eod eoe eok eoo eor eot erc erd ere erk ero err ert etc etd ete etk eto etr ett k-t kcc kcd kce kck kcr kct kdc kde kdk kdo kdr kdt ke- kec ked kee kek keo ker ket kkc kke kkk kkr kkt koc kod koe kok koo kor kot krc krd krk kro krr krt ktc kte ktk kto ktr ktt oc- occ ocd ock oco ocr oct odc odd ode odo odr odt oec oed oee oeo oer oet okc okd oke okk oko okr oo- ooc ood ook ooo oor oot or- orc ord ore ork oro orr ort ot- otc otd ote otk oto otr ott rcc rcd rce rco rcr rct rdc rdd rde rdo rdr rdt re- rec red ree rek reo rer ret rkc rke rkk rko rkt roc rod roe rok roo ror rot rrc rrd rrk rrr rrt rtc rtd rte rtk rto rtr rtt tcc tcd tce tck tco tcr tct tdc tdd tde tdk tdo tdr tdt te- tec ted tee tek teo ter tet tkc tke tkk tko tkr tkt to- toc tod toe tok too tor tot trc trd tre trk tro trr trt ttc ttd tte ttk tto ttr ttt