-er c-- ccc cce cck ccl ccr ccs ce- cec cee cek cel cer ces ckc cks cl- clc cle clk cll clr cls crc cre crk crl crr crs csc cse csk csl csr css ec- ecc ece eck ecl ecr ecs eec eee eek eel eer ees ekc eke ekl ekr eks elc ele elk ell elr els erc ere erk erl err ers es- esc ese esk esl esr ess kcc kce kck kcl kcr kcs ke- kec kee kek kel ker kes kkc kke kkk kkl kkr kks kl- klc klr kls krc krk krl krr krs ksc kse ksk ksl ksr kss lcc lce lck lcl lcr lcs lec lee lek lel ler les lkl lkr lks llc lle llk lll llr lls lrc lrk lrr lrs lsc lse lsk lsl lsr lss rcc rce rcl rcr rcs re- rec ree rek rel rer res rkc rke rkk rks rlc rle rll rlr rls rrc rrk rrl rrr rrs rsc rse rsk rsl rsr rss scc sce sck scl scr scs se- sec see sek sel ser ses sk- skc ske skk skl skr sks slc sle slk sll slr sls sr- src sre srk srl srr srs ss- ssc sse ssk ssl ssr sss