-er c-- ccc ccd cce cco ccr ccs cdc cdd cde cdo cdr cds ce- cec ced cee ceo cer ces co- coc cod coe coo cor cos crc crd cre cro crr crs csc csd cse cso csr css dcc dcd dce dco dcr dcs ddc ddd dde ddo ddr dds de- dec ded dee deo der des doc dod doe doo dor dos drc drd dre dro drr drs dsc dsd dse dso dsr dss ec- ecc ecd ece eco ecr ecs ed- edc edd ede edo edr eds eec eed eee eeo eer ees eo- eoc eod eoe eoo eor eos erc erd ere ero err ers es- esc esd ese eso esr ess oc- occ ocd oco ocr ocs odc odd ode odo odr ods oec oed oee oeo oer oes oo- ooc ood ooo oor oos or- orc ord ore oro orr ors os- osc osd ose oso osr oss rcc rcd rce rco rcr rcs rdc rdd rde rdo rdr rds re- rec red ree reo rer res roc rod roe roo ror ros rrc rrd rrr rrs rsc rsd rse rso rsr rss scc scd sce sco scr scs sdc sdd sde sdo sdr sds se- sec sed see seo ser ses soc sod soe soo sor sos sr- src srd sre sro srr srs ss- ssc ssd sse sso ssr sss