-er c-- ccc cce ccf ccn ccr ccs ce- cec cee cef cen cer ces cfc cfe cff cfn cfr cfs cn- cnc cne cnf cnn cnr cns crc cre crf crn crr crs csc cse csf csn csr css ec- ecc ece ecf ecn ecr ecs eec eee eef een eer ees ef- efc efe eff efr efs en- enc ene enf enn enr ens erc ere erf ern err ers es- esc ese esf esn esr ess fcc fce fcf fcn fcr fcs fec fee fef fen fer fes ffc ffe fff ffn ffr ffs fnc fne fnf fnn fnr fns frc fre frf frn frr frs fsc fse fsf fsn fsr fss ncc nce ncf ncn ncr ncs ne- nec nee nef nen ner nes nfc nfe nff nfn nfr nfs nnc nne nnf nnn nns nrc nre nrf nrn nrr nrs nsc nse nsf nsn nsr nss rcc rce rcf rcn rcr rcs re- rec ree ref ren rer res rfc rfe rff rfn rfr rfs rnc rnn rnr rns rrc rrf rrn rrr rrs rsc rse rsf rsn rsr rss scc sce scf scn scr scs se- sec see sef sen ser ses sfc sfe sff sfn sfr sfs snc sne snf snn snr sns sr- src sre srf srn srr srs ss- ssc sse ssf ssn ssr sss