-er c-- ccc cce cco ccp ccr cct ce- cec cee ceo cep cer cet co- coc coe coo cop cor cot cpc cpe cpo cpp cpr cpt crc cre cro crp crr crt ctc cte cto ctp ctr ctt ec- ecc ece eco ecr ect eec eee eeo eep eer eet eo- eoc eoe eoo eop eor eot ep- epc epe epo epp epr ept erc ere ero erp err ert etc ete eto etp etr ett oc- occ oco ocp ocr oct oec oee oeo oep oer oet oo- ooc ooo oop oor oot op- opc ope opo opp opr opt or- orc ore oro orp orr ort ot- otc ote oto otp otr ott p-p pcc pce pco pcp pcr pct pec pee peo pep per pet poc poe poo pop por pot ppc ppe ppo ppp ppr ppt prc pre pro prp prr prt pt- ptc pte pto ptp ptr ptt rcc rce rco rcp rcr rct re- rec ree reo rep rer ret roc roe roo rop ror rot rpc rpe rpo rpp rpr rpt rrc rrp rrr rrt rtc rte rto rtp rtr rtt tcc tce tco tcp tcr tct te- tec tee teo tep ter tet to- toc toe too top tor tot tpc tpe tpo tpp tpr tpt trc tre tro trp trr trt ttc tte tto ttp ttr ttt