-er c-- ccc cce cck ccn cco ccr ce- cec cee cek cen ceo cer ckc cko cn- cnc cne cnn cno cnr co- coc coe cok con coo cor crc cre crk crn cro crr ec- ecc ece eck ecn eco ecr eec eee eek een eeo eer ekc eke eko ekr en- enc ene enk enn eno enr eo- eoc eoe eok eon eoo eor erc ere erk ern ero err kcc kce kck kcn kcr ke- kec kee kek ken keo ker kkc kke kkk kkn kkr kn- knc kne knk knn kno knr koc koe kok kon koo kor krc krk krn kro krr ncc nce nck ncn nco ncr ne- nec nee nek nen neo ner nkc nke nkk nkn nko nkr nnc nne nnk nnn nno no- noc noe nok non noo nor nrc nre nrk nrn nro nrr oc- occ ock ocn oco ocr oec oee oen oeo oer okc oke okk oko okr on- onc one onk onn ono onr oo- ooc ook oon ooo oor or- orc ore ork orn oro orr rcc rce rcn rco rcr re- rec ree rek ren reo rer rkc rke rkk rko rnc rnn rno rnr roc roe rok ron roo ror rrc rrk rrn rrr