c-- ccc ccf cck ccs ccu cfc cff cfk cfs cfu ckc cks csc csf csk css csu cuc cuf cuk cus cuu fcc fcf fck fcs fcu ffc fff ffk ffs ffu fkc fkf fkk fsc fsf fsk fss fsu fuf fuk fus fuu kcc kck kcs kcu kfc kff kfs kfu kkc kkk kks kku ksc ksf ksk kss ksu kuc kuk kus kuu scc scf sck scs scu sfc sff sfk sfs sfu sk- skc skf skk sks sku ss- ssc ssf ssk sss ssu suc suf suk sus suu ucc ucf uck ucs ucu ufc uff ufs ufu ukc ukf ukk uku usc usf usk uss usu uuc uus uuu