-er eee eek eeo eer ees eie eii eik eio eir eis eke eki eko ekr eks eo- eoe eoi eok eoo eor eos ere eri erk ero err ers es- ese esi esk eso esr ess ie- iee iei iek ier ies iie iii iio iir iis ike iki ikk iko ikr iks io- ioe ioi ioo ior ios ir- ire iri irk iro irr irs is- ise isi isk iso isr iss ke- kee kei kek keo ker kes kie kii kik kio kir kis kke kki kkk kkr kks koe koi kok koo kor kos kri krk kro krr krs kse ksi ksk kso ksr kss o-i oee oei oeo oer oes oie oii oik oio oir ois oke oki okk oko okr oks oo- ooi ook ooo oor oos or- ore ori ork oro orr ors os- ose osi osk oso osr oss re- ree rei rek reo rer res rie rii rik rio rir ris rke rkk rko rks roe roi rok roo ror ros rri rrk rrr rrs rse rsi rsk rso rsr rss se- see sei sek seo ser ses sie sii sik sio sir sis sk- ske ski skk sko skr sks soe soi sok soo sor sos sr- sre sri srk sro srr srs ss- sse ssi ssk sso ssr sss