-er c-- ccc ccd cce cck ccr ccu cdc cdd cde cdk cdr cdu ce- cec ced cee cek cer ceu ckc ckd crc crd cre crk crr cru cuc cud cue cuk cur cuu dcc dcd dce dck dcr dcu ddc ddd dde ddk ddr ddu de- dec ded dee dek der deu dkc dke dkk dkr dku drc drd dre drk drr dru duc dud due duk dur ec- ecc ecd ece eck ecr ecu ed- edc edd ede edk edr edu eec eed eee eek eer ekc ekd eke ekr eku erc erd ere erk err eru eu- euc eud eue eur kcc kcd kce kck kcr kcu kdc kde kdk kdr kdu ke- kec ked kee kek ker kkc kke kkk kkr kku krc krd krk krr kru kuc kud kue kuk kur kuu rcc rcd rce rcr rcu rdc rdd rde rdr rdu re- rec red ree rek rer reu rkc rke rkk rku rrc rrd rrk rrr rru ruc rud rue ruk rur ruu ucc ucd uce uck ucr ucu udc udd ude udk udr udu uec ued uee uer ukc uke ukk ukr uku ur- urc urd ure urk urr uru uuc uue uur uuu