c-- ccc ccf cck cco ccu cfc cff cfk cfo cfu ckc cko cky co- coc cof cok coo cou coy cuc cuf cuk cuo cuu cuy cyc cyf cyk cyo fcc fcf fck fco fcu fcy ffc fff ffk ffo ffu ffy fkc fkf fkk foc fof fok foo fou foy fuf fuk fuo fuu fy- fyc fyk fyo kcc kck kcu kfc kff kfo kfu kkc kkk kku kky koc kof kok koo kou koy kuc kuk kuu kuy kyc kyo kyu oc- occ ocf ock oco ocu of- ofc off ofo ofu okc okk oko oku oo- ooc oof ook ooo ou- ouc ouf ouk ouo oyo ucc ucf uck uco ucu ufc uff ufo ufu ukc ukf ukk uku uoc uok uoo uuc uuu uyc uyo uyu ycc ycf yco ycu ycy yfc yff yfu ykk yoc yof yok yoo you yoy yuk yuo yuu yuy yyc yyf yyu yyy