c-- ccc cck cco ccr ccs ccu ckc cko cks co- coc cok coo cor cos cou crc crk cro crr crs cru csc csk cso csr css csu cuc cuk cuo cur cus cuu kcc kck kcr kcs kcu kkc kkk kkr kks kku koc kok koo kor kos kou krc krk kro krr krs kru ksc ksk kso ksr kss ksu kuc kuk kur kus kuu oc- occ ock oco ocr ocs ocu okc okk oko okr oks oku oo- ooc ook ooo oor oos or- orc ork oro orr ors oru os- osc osk oso osr oss osu ou- ouc ouk ouo our ous rcc rco rcr rcs rcu rkc rkk rko rks rku roc rok roo ror ros rou rrc rrk rrr rrs rru rsc rsk rso rsr rss rsu ruc ruk ruo rur rus ruu scc sck sco scr scs scu sk- skc skk sko skr sks sku soc sok soo sor sos sou sr- src srk sro srr srs ss- ssc ssk sso ssr sss ssu suc suk suo sur sus suu ucc uck uco ucr ucs ucu ukc ukk ukr uku uoc uok uoo uor uos ur- urc urk uro urr urs uru usc usk uso usr uss usu uuc uur uus uuu