c-- ccc ccf ccr ccs ccu cfc cff cfr cfs cfu crc crf crr crs cru csc csf csr css csu cuc cuf cur cus cuu fcc fcf fcr fcs fcu ffc fff ffr ffs ffu frc frf frr frs fru fsc fsf fsr fss fsu fuf fur fus fuu rcc rcf rcr rcs rcu rfc rff rfr rfs rfu rrc rrf rrr rrs rru rsc rsf rsr rss rsu ruc ruf rur rus ruu scc scf scr scs scu sfc sff sfr sfs sfu sr- src srf srr srs ss- ssc ssf ssr sss ssu suc suf sur sus suu ucc ucf ucr ucs ucu ufc uff ufr ufs ufu ur- urc urf urr urs uru usc usf usr uss usu uuc uur uus uuu