-er c-- ccc ccd cce cck cco ccr ccu cdc cdd cde cdk cdo cdr cdu ce- cec ced cee cek ceo cer ceu ckc ckd cko co- coc cod coe cok coo cor cou crc crd cre crk cro crr cru cuc cud cue cuk cuo cur cuu dcc dcd dce dck dco dcr dcu ddc ddd dde ddk ddo ddr ddu de- dec ded dee dek deo der deu dkc dke dkk dko dkr dku doc dod doe dok doo dor dou drc drd dre drk dro drr dru duc dud due duk duo dur ec- ecc ecd ece eck eco ecr ecu ed- edc edd ede edk edo edr edu eec eed eee eek eeo eer ekc ekd eke eko ekr eku eo- eoc eod eoe eok eoo eor eou erc erd ere erk ero err eru eu- euc eud eue eur kcc kcd kce kck kcr kcu kdc kde kdk kdo kdr kdu ke- kec ked kee kek keo ker kkc kke kkk kkr kku koc kod koe kok koo kor kou krc krd krk kro krr kru kuc kud kue kuk kur kuu oc- occ ocd ock oco ocr ocu odc odd ode odo odr odu oec oed oee oeo oer okc okd oke okk oko okr oku oo- ooc ood ook ooo oor or- orc ord ore ork oro orr oru ou- ouc oud oue ouk ouo our rcc rcd rce rco rcr rcu rdc rdd rde rdo rdr rdu re- rec red ree rek reo rer reu rkc rke rkk rko rku roc rod roe rok roo ror rou rrc rrd rrk rrr rru ruc rud rue ruk ruo rur ruu ucc ucd uce uck uco ucr ucu udc udd ude udk udo udr udu uec ued uee uer ukc uke ukk ukr uku uoc uod uoe uok uoo uor ur- urc urd ure urk uro urr uru uuc uue uur uuu