-er -ic c-- ccc cce ccf cci cck ccr ccs ce- cec cee cef cei cek cer ces cfc cfe cff cfi cfk cfr cfs ci- cic cie cif cii cik cir cis ckc cki cks crc cre crf cri crk crr crs csc cse csf csi csk csr css ec- ecc ece ecf eci eck ecr ecs eec eee eef eek eer ees ef- efc efe eff efi efr efs eic eie eif eii eik eir eis ekc eke ekf eki ekr eks erc ere erf eri erk err ers es- esc ese esf esi esk esr ess fcc fce fcf fci fck fcr fcs fec fee fef fei fek fer fes ffc ffe fff ffi ffk ffr ffs fic fie fif fii fik fir fis fkc fkf fki fkk frc fre frf fri frk frr frs fsc fse fsf fsi fsk fsr fss i-f icc ice icf ici ick icr ics ie- iec iee ief iei iek ier ies ifc ife iff ifi ifr ifs iic iie iif iii iir iis ikc ike ikf iki ikk ikr iks ir- irc ire irf iri irk irr irs is- isc ise isf isi isk isr iss kcc kce kci kck kcr kcs ke- kec kee kef kei kek ker kes kfc kff kfi kfs kic kie kif kii kik kir kis kkc kke kki kkk kkr kks krc krf kri krk krr krs ksc kse ksf ksi ksk ksr kss rcc rce rcf rci rcr rcs re- rec ree ref rei rek rer res rfc rfe rff rfi rfk rfr rfs ric rie rif rii rik rir ris rkc rke rkf rkk rks rrc rrf rri rrk rrr rrs rsc rse rsf rsi rsk rsr rss scc sce scf sci sck scr scs se- sec see sef sei sek ser ses sfc sfe sff sfi sfk sfr sfs sic sie sif sii sik sir sis sk- skc ske skf ski skk skr sks sr- src sre srf sri srk srr srs ss- ssc sse ssf ssi ssk ssr sss