c-- ccc ccd cck cco ccr cct cdc cdd cdk cdo cdr cdt ckc ckd cko ckt co- coc cod cok coo cor cot crc crd crk cro crr crt ctc ctd ctk cto ctr ctt dcc dcd dck dco dcr dct ddc ddd ddk ddo ddr ddt dkc dkk dko dkr dkt doc dod dok doo dor dot drc drd drk dro drr drt dtc dtd dtk dto dtr dtt k-t kcc kcd kck kcr kct kdc kdk kdo kdr kdt kkc kkk kkr kkt koc kod kok koo kor kot krc krd krk kro krr krt ktc ktk kto ktr ktt oc- occ ocd ock oco ocr oct odc odd odo odr odt okc okd okk oko okr oo- ooc ood ook ooo oor oot or- orc ord ork oro orr ort ot- otc otd otk oto otr ott rcc rcd rco rcr rct rdc rdd rdo rdr rdt rkc rkk rko rkt roc rod rok roo ror rot rrc rrd rrk rrr rrt rtc rtd rtk rto rtr rtt tcc tcd tck tco tcr tct tdc tdd tdk tdo tdr tdt tkc tkk tko tkr tkt to- toc tod tok too tor tot trc trd trk tro trr trt ttc ttd ttk tto ttr ttt