c-- ccc ccd cck cco cct ccu cdc cdd cdk cdo cdt cdu ckc ckd cko ckt co- coc cod cok coo cot cou ctc ctd ctk cto ctt ctu cuc cud cuk cuo cut cuu dcc dcd dck dco dct dcu ddc ddd ddk ddo ddt ddu dkc dkk dko dkt dku doc dod dok doo dot dou dtc dtd dtk dto dtt dtu duc dud duk duo dut k-t kcc kcd kck kct kcu kdc kdk kdo kdt kdu kkc kkk kkt kku koc kod kok koo kot kou ktc ktk kto ktt ktu kuc kud kuk kut kuu oc- occ ocd ock oco oct ocu odc odd odo odt odu okc okd okk oko oku oo- ooc ood ook ooo oot ot- otc otd otk oto ott otu ou- ouc oud ouk ouo out tcc tcd tck tco tct tcu tdc tdd tdk tdo tdt tdu tkc tkk tko tkt to- toc tod tok too tot tou ttc ttd ttk tto ttt ttu tuc tud tuk tuo tut tuu ucc ucd uck uco uct ucu udc udd udk udo udt udu ukc ukk uku uoc uod uok uoo uot utc utd utk uto utt utu uuc uut uuu