c-- ccc ccd cck ccn cco ccr cdc cdd cdk cdn cdo cdr ckc ckd cko cn- cnc cnd cnn cno cnr co- coc cod cok con coo cor crc crd crk crn cro crr dcc dcd dck dcn dco dcr ddc ddd ddk ddn ddo ddr dkc dkk dko dkr dnc dnd dnk dnn dno dnr doc dod dok don doo dor drc drd drk drn dro drr kcc kcd kck kcn kcr kdc kdk kdo kdr kkc kkk kkn kkr kn- knc knd knk knn kno knr koc kod kok kon koo kor krc krd krk krn kro krr ncc ncd nck ncn nco ncr ndc ndd ndk ndn ndo ndr nkc nkk nkn nko nkr nnc nnk nnn nno no- noc nod nok non noo nor nrc nrd nrk nrn nro nrr oc- occ ocd ock ocn oco ocr odc odd odn odo odr okc okd okk oko okr on- onc ond onk onn ono onr oo- ooc ood ook oon ooo oor or- orc ord ork orn oro orr rcc rcd rcn rco rcr rdc rdd rdn rdo rdr rkc rkk rko rnc rnd rnn rno rnr roc rod rok ron roo ror rrc rrd rrk rrn rrr