-er c-- ccc ccd cce cco ccr ccv cdc cdd cde cdo cdr cdv ce- cec ced cee ceo cer cev co- coc cod coe coo cor cov crc crd cre cro crr crv cvc cvd cve cvo cvr cvv dcc dcd dce dco dcr dcv ddc ddd dde ddo ddr de- dec ded dee deo der dev doc dod doe doo dor dov drc drd dre dro drr drv dvc dvd dve dvr ec- ecc ecd ece eco ecr ecv ed- edc edd ede edo edr eec eed eee eeo eer eev eo- eoc eod eoe eoo eor erc erd ere ero err erv evc evd eve evo evr evv oc- occ ocd oco ocr ocv odc odd ode odo odr odv oec oed oee oeo oer oo- ooc ood ooo oor oov or- orc ord ore oro orr orv ov- ovc ovd ove ovo ovv rcc rcd rce rco rcr rcv rdc rdd rde rdo rdr rdv re- rec red ree reo rer rev roc rod roe roo ror rov rrc rrd rrr rvc rvd rve rvo rvr rvv v-e vcc vcd vce vco vcr vdc vdd vde vdo vdr vdv vec ved vee veo ver voc vod voe voo vor vov vrc vrd vre vrr vvc vvo vvr vvv