-er c-- ccc cce ccp ccr cct ccx ce- cec cee cep cer cet cex cpc cpe cpp cpr cpt cpx crc cre crp crr crt crx ctc cte ctp ctr ctt ctx cxc cxp cxr cxt cxx ec- ecc ece ecr ect ecx eec eee eep eer eet eex ep- epc epe epp epr ept epx erc ere erp err ert etc ete etp etr ett etx ex- exc exe exp exr ext exx p-p pcc pce pcp pcr pct pcx pec pee pep per pet pex ppc ppe ppp ppr ppt ppx prc pre prp prr prt prx pt- ptc pte ptp ptr ptt ptx pxc pxe pxr pxt rcc rce rcp rcr rct rcx re- rec ree rep rer ret rex rpc rpe rpp rpr rpt rpx rrc rrp rrr rrt rtc rte rtp rtr rtt rtx rxp rxr t-x tcc tce tcp tcr tct tcx te- tec tee tep ter tet tex tpc tpe tpp tpr tpt tpx trc tre trp trr trt trx ttc tte ttp ttr ttt ttx txe txt xcp xcr xcx xee xep xer xet xex xpc xpe xpp xpt xrc xrt xrx xtc xtp xtr xtx xxp xxx