-er c-- ccc cce ccn cco ccr ccs ce- cec cee cen ceo cer ces cn- cnc cne cnn cno cnr cns co- coc coe con coo cor cos crc cre crn cro crr crs csc cse csn cso csr css ec- ecc ece ecn eco ecr ecs eec eee een eeo eer ees en- enc ene enn eno enr ens eo- eoc eoe eon eoo eor eos erc ere ern ero err ers es- esc ese esn eso esr ess ncc nce ncn nco ncr ncs ne- nec nee nen neo ner nes nnc nne nnn nno nns no- noc noe non noo nor nos nrc nre nrn nro nrr nrs nsc nse nsn nso nsr nss oc- occ ocn oco ocr ocs oec oee oen oeo oer oes on- onc one onn ono onr ons oo- ooc oon ooo oor oos or- orc ore orn oro orr ors os- osc ose osn oso osr oss rcc rce rcn rco rcr rcs re- rec ree ren reo rer res rnc rnn rno rnr rns roc roe ron roo ror ros rrc rrn rrr rrs rsc rse rsn rso rsr rss scc sce scn sco scr scs se- sec see sen seo ser ses snc sne snn sno snr sns soc soe son soo sor sos sr- src sre srn sro srr srs ss- ssc sse ssn sso ssr sss