-er a-a a-c aaa aac aae aak aan aar aas ac- aca acc ace ack acn acr acs aea aec aee aek aen aer aes aka akc ake akk akn akr aks an- ana anc ane ank ann anr ans ar- ara arc are ark arn arr ars as- asa asc ase ask asn asr ass c-- caa cac cae cak can car cas cca ccc cce cck ccn ccr ccs ce- cea cec cee cek cen cer ces cka ckc cks cn- cna cnc cne cnn cnr cns cra crc cre crk crn crr crs csa csc cse csk csn csr css eaa eac eae eak ean ear eas ec- eca ecc ece eck ecn ecr ecs eea eec eee eek een eer ees eka ekc eke ekr eks en- ena enc ene enk enn enr ens era erc ere erk ern err ers es- esa esc ese esk esn esr ess ka- kaa kac kae kak kan kar kas kca kcc kce kck kcn kcr kcs ke- kea kec kee kek ken ker kes kkc kke kkk kkn kkr kks kn- kna knc kne knk knn knr kra krc krk krn krr krs ksa ksc kse ksk ksn ksr kss naa nac nae nak nan nar nas nca ncc nce nck ncn ncr ncs ne- nea nec nee nek nen ner nes nka nkc nke nkk nkn nkr nks nna nnc nne nnk nnn nns nra nrc nre nrk nrn nrr nrs nsa nsc nse nsk nsn nsr nss ra- raa rac rae rak ran rar ras rca rcc rce rcn rcr rcs re- rea rec ree rek ren rer res rkc rke rkk rks rna rnc rnn rnr rns rra rrc rrk rrn rrr rrs rsa rsc rse rsk rsn rsr rss saa sac sae sak san sar sas sca scc sce sck scn scr scs se- sea sec see sek sen ser ses sk- ska skc ske skk skr sks sna snc sne snk snn snr sns sr- sra src sre srk srn srr srs ss- ssa ssc sse ssk ssn ssr sss