c-- ccc ccr ccs cct ccu crc crr crs crt cru csc csr css cst csu ctc ctr cts ctt ctu cuc cur cus cut cuu rcc rcr rcs rct rcu rrc rrr rrs rrt rru rsc rsr rss rst rsu rtc rtr rts rtt rtu ruc rur rus rut ruu scc scr scs sct scu sr- src srr srs srt ss- ssc ssr sss sst ssu stc str sts stt stu suc sur sus sut suu tcc tcr tcs tct tcu trc trr trs trt tru tsc tsr tss tst tsu ttc ttr tts ttt ttu tuc tur tus tut tuu ucc ucr ucs uct ucu ur- urc urr urs urt uru usc usr uss ust usu utc utr uts utt utu uuc uur uus uut uuu