-er ddd dde ddi ddk ddo ddr dds de- ded dee dei dek deo der des di- did die dii dik dio dir dis dke dki dkk dko dkr dks dod doe doi dok doo dor dos drd dre dri drk dro drr drs dsd dse dsi dsk dso dsr dss ed- edd ede edi edk edo edr eds eed eee eek eeo eer ees eid eie eii eik eio eir eis ekd eke eki eko ekr eks eo- eod eoe eoi eok eoo eor eos erd ere eri erk ero err ers es- esd ese esi esk eso esr ess i-d idd ide idi idk ido idr ids ie- ied iee iei iek ier ies iid iie iii iio iir iis ike iki ikk iko ikr iks io- iod ioe ioi ioo ior ios ir- ird ire iri irk iro irr irs is- isd ise isi isk iso isr iss kde kdk kdo kdr kds ke- ked kee kei kek keo ker kes kid kie kii kik kio kir kis kke kki kkk kkr kks kod koe koi kok koo kor kos krd kri krk kro krr krs ksd kse ksi ksk kso ksr kss o-i odd ode odi odo odr ods oed oee oei oeo oer oes oid oie oii oik oio oir ois okd oke oki okk oko okr oks oo- ood ooi ook ooo oor oos or- ord ore ori ork oro orr ors os- osd ose osi osk oso osr oss rdd rde rdi rdo rdr rds re- red ree rei rek reo rer res rid rie rii rik rio rir ris rke rkk rko rks rod roe roi rok roo ror ros rrd rri rrk rrr rrs rsd rse rsi rsk rso rsr rss sdd sde sdi sdk sdo sdr sds se- sed see sei sek seo ser ses sid sie sii sik sio sir sis sk- skd ske ski skk sko skr sks sod soe soi sok soo sor sos sr- srd sre sri srk sro srr srs ss- ssd sse ssi ssk sso ssr sss