-er -ic c-- ccc ccd cce cci cck cco ccr cdc cdd cde cdi cdk cdo cdr ce- cec ced cee cei cek ceo cer ci- cic cid cie cii cik cio cir ckc ckd cki cko co- coc cod coe coi cok coo cor crc crd cre cri crk cro crr dcc dcd dce dci dck dco dcr ddc ddd dde ddi ddk ddo ddr de- dec ded dee dei dek deo der di- dic did die dii dik dio dir dkc dke dki dkk dko dkr doc dod doe doi dok doo dor drc drd dre dri drk dro drr ec- ecc ecd ece eci eck eco ecr ed- edc edd ede edi edk edo edr eec eed eee eek eeo eer eic eid eie eii eik eio eir ekc ekd eke eki eko ekr eo- eoc eod eoe eoi eok eoo eor erc erd ere eri erk ero err i-d icc icd ice ici ick ico icr idc idd ide idi idk ido idr ie- iec ied iee iei iek ier iic iid iie iii iio iir ikc ike iki ikk iko ikr io- ioc iod ioe ioi ioo ior ir- irc ird ire iri irk iro irr kcc kcd kce kci kck kcr kdc kde kdk kdo kdr ke- kec ked kee kei kek keo ker kic kid kie kii kik kio kir kkc kke kki kkk kkr koc kod koe koi kok koo kor krc krd kri krk kro krr o-i oc- occ ocd oci ock oco ocr odc odd ode odi odo odr oec oed oee oei oeo oer oic oid oie oii oik oio oir okc okd oke oki okk oko okr oo- ooc ood ooi ook ooo oor or- orc ord ore ori ork oro orr rcc rcd rce rci rco rcr rdc rdd rde rdi rdo rdr re- rec red ree rei rek reo rer ric rid rie rii rik rio rir rkc rke rkk rko roc rod roe roi rok roo ror rrc rrd rri rrk rrr