-er c-- ccc cce cck cco ccr ccz ce- cec cee cek ceo cer cez ckc cko co- coc coe cok coo cor coz crc cre crk cro crr crz cz- czc cze czk czo ec- ecc ece eck eco ecr eec eee eek eeo eer ekc eke eko ekr eo- eoc eoe eok eoo eor erc ere erk ero err erz eze ezo ezr ezz k-z kcc kce kck kcr ke- kec kee kek keo ker kez kkc kke kkk kkr koc koe kok koo kor koz krc krk kro krr kzo oc- occ ock oco ocr ocz oec oee oeo oer okc oke okk oko okr oo- ooc ook ooo oor or- orc ore ork oro orr orz oze ozo ozz rcc rce rco rcr re- rec ree rek reo rer rez rkc rke rkk rko rkz roc roe rok roo ror roz rrc rrk rrr rze rzo zce zco zec zee zek zeo zer zez zo- zoc zoe zok zoo zor zro zzr zzz