-er ddd dde ddi ddk ddo ddp ddr dds de- ded dee dei dek deo dep der des di- did die dii dik dio dip dir dis dke dki dkk dko dkp dkr dks dod doe doi dok doo dop dor dos dpd dpe dpi dpk dpo dpp dpr dps drd dre dri drk dro drp drr drs dsd dse dsi dsk dso dsp dsr dss ed- edd ede edi edk edo edp edr eds eed eee eek eeo eep eer ees eid eie eii eik eio eip eir eis ekd eke eki eko ekp ekr eks eo- eod eoe eoi eok eoo eop eor eos ep- epd epe epi epo epp epr eps erd ere eri erk ero erp err ers es- esd ese esi esk eso esp esr ess i-d idd ide idi idk ido idp idr ids ie- ied iee iei iek iep ier ies iid iie iii iio iip iir iis ike iki ikk iko ikr iks io- iod ioe ioi ioo iop ior ios ipd ipe ipi ipo ipp ipr ips ir- ird ire iri irk iro irp irr irs is- isd ise isi isk iso isp isr iss kde kdk kdo kdp kdr kds ke- ked kee kei kek keo kep ker kes kid kie kii kik kio kip kir kis kke kki kkk kkp kkr kks kod koe koi kok koo kop kor kos kpd kpe kpi kpk kpo kpp kpr kps krd kri krk kro krp krr krs ksd kse ksi ksk kso ksp ksr kss o-i odd ode odi odo odp odr ods oed oee oei oeo oep oer oes oid oie oii oik oio oip oir ois okd oke oki okk oko okp okr oks oo- ood ooi ook ooo oop oor oos op- opd ope opi opk opo opp opr ops or- ord ore ori ork oro orp orr ors os- osd ose osi osk oso osp osr oss p-p pdd pde pdi pdk pdo pdp pdr pds ped pee pei pek peo pep per pes pid pie pii pik pio pip pir pis pkd pke pki pko pkp pkr pks pod poe poi pok poo pop por pos ppd ppe ppi ppk ppo ppp ppr pps prd pre pri prk pro prp prr prs ps- psd pse psi psk pso psp psr pss rdd rde rdi rdo rdp rdr rds re- red ree rei rek reo rep rer res rid rie rii rik rio rip rir ris rke rkk rko rkp rks rod roe roi rok roo rop ror ros rpd rpe rpi rpk rpo rpp rpr rps rrd rri rrk rrp rrr rrs rsd rse rsi rsk rso rsp rsr rss sdd sde sdi sdk sdo sdp sdr sds se- sed see sei sek seo sep ser ses sid sie sii sik sio sip sir sis sk- skd ske ski skk sko skp skr sks sod soe soi sok soo sop sor sos spd spe spi spk spo spp spr sps sr- srd sre sri srk sro srp srr srs ss- ssd sse ssi ssk sso ssp ssr sss