-er c-- ccc cce ccr ccs cct ccu ce- cec cee cer ces cet ceu crc cre crr crs crt cru csc cse csr css cst csu ctc cte ctr cts ctt ctu cuc cue cur cus cut cuu ec- ecc ece ecr ecs ect ecu eec eee eer ees eet erc ere err ers ert eru es- esc ese esr ess est esu etc ete etr ets ett etu eu- euc eue eur eus eut rcc rce rcr rcs rct rcu re- rec ree rer res ret reu rrc rrr rrs rrt rru rsc rse rsr rss rst rsu rtc rte rtr rts rtt rtu ruc rue rur rus rut ruu scc sce scr scs sct scu se- sec see ser ses set seu sr- src sre srr srs srt ss- ssc sse ssr sss sst ssu stc ste str sts stt stu suc sue sur sus sut suu tcc tce tcr tcs tct tcu te- tec tee ter tes tet teu trc tre trr trs trt tru tsc tse tsr tss tst tsu ttc tte ttr tts ttt ttu tuc tue tur tus tut tuu ucc uce ucr ucs uct ucu uec uee uer ues uet ur- urc ure urr urs urt uru usc use usr uss ust usu utc ute utr uts utt utu uuc uue uur uus uut uuu