-er c-- ccc cce cck ccm ccr ccx ce- cec cee cek cem cer cex ckc ckm ckx cmc cme cmk cmm cmr cmx crc cre crk crm crr crx cxc cxk cxr cxx ec- ecc ece eck ecm ecr ecx eec eee eek eem eer eex ekc eke ekr em- emc eme emk emm emr emx erc ere erk erm err ex- exc exe exr exx kcc kce kck kcm kcr kcx ke- kec kee kek kem ker kex kkc kke kkk kkm kkr kmc kme kmk kmm krc krk krr kxm m-r mc- mcc mce mck mcm mcr mcx mec mee mek mem mer mex mkc mke mkk mkm mkr mkx mmc mme mmk mmm mmr mmx mrc mre mrk mrm mrr mrx mxc mxr rcc rce rcm rcr rcx re- rec ree rek rem rer rex rkc rke rkk rkm rmc rme rmm rmr rmx rrc rrk rrm rrr rxr xcr xcx xee xem xer xex xke xmc xmk xmm xmr xmx xrc xrx xxx