-er c-- ccc ccd cce cck ccr ccs cdc cdd cde cdk cdr cds ce- cec ced cee cek cer ces ckc ckd cks crc crd cre crk crr crs csc csd cse csk csr css dcc dcd dce dck dcr dcs ddc ddd dde ddk ddr dds de- dec ded dee dek der des dkc dke dkk dkr dks drc drd dre drk drr drs dsc dsd dse dsk dsr dss ec- ecc ecd ece eck ecr ecs ed- edc edd ede edk edr eds eec eed eee eek eer ees ekc ekd eke ekr eks erc erd ere erk err ers es- esc esd ese esk esr ess kcc kcd kce kck kcr kcs kdc kde kdk kdr kds ke- kec ked kee kek ker kes kkc kke kkk kkr kks krc krd krk krr krs ksc ksd kse ksk ksr kss rcc rcd rce rcr rcs rdc rdd rde rdr rds re- rec red ree rek rer res rkc rke rkk rks rrc rrd rrk rrr rrs rsc rsd rse rsk rsr rss scc scd sce sck scr scs sdc sdd sde sdk sdr sds se- sec sed see sek ser ses sk- skc skd ske skk skr sks sr- src srd sre srk srr srs ss- ssc ssd sse ssk ssr sss