-er -ol c-- ccc cce cck ccl cco ccr ccs ce- cec cee cek cel ceo cer ces ckc cko cks cl- clc cle clk cll clo clr cls co- coc coe cok col coo cor cos crc cre crk crl cro crr crs csc cse csk csl cso csr css ec- ecc ece eck ecl eco ecr ecs eec eee eek eel eeo eer ees ekc eke ekl eko ekr eks elc ele elk ell elo elr els eo- eoc eoe eok eol eoo eor eos erc ere erk erl ero err ers es- esc ese esk esl eso esr ess kcc kce kck kcl kcr kcs ke- kec kee kek kel keo ker kes kkc kke kkk kkl kkr kks kl- klc klo klr kls koc koe kok kol koo kor kos krc krk krl kro krr krs ksc kse ksk ksl kso ksr kss lcc lce lck lcl lco lcr lcs lec lee lek lel leo ler les lkl lkr lks llc lle llk lll llo llr lls loc loe lok lol loo lor los lrc lrk lro lrr lrs lsc lse lsk lsl lso lsr lss oc- occ ock ocl oco ocr ocs oec oee oel oeo oer oes okc oke okk okl oko okr oks olc ole olk oll olo ols oo- ooc ook ool ooo oor oos or- orc ore ork orl oro orr ors os- osc ose osk osl oso osr oss rcc rce rcl rco rcr rcs re- rec ree rek rel reo rer res rkc rke rkk rko rks rlc rle rll rlo rlr rls roc roe rok rol roo ror ros rrc rrk rrl rrr rrs rsc rse rsk rsl rso rsr rss scc sce sck scl sco scr scs se- sec see sek sel seo ser ses sk- skc ske skk skl sko skr sks slc sle slk sll slo slr sls soc soe sok sol soo sor sos sr- src sre srk srl sro srr srs ss- ssc sse ssk ssl sso ssr sss