-er eee eef een eep eer eet ef- efe eff efp efr eft en- ene enf enn enp enr ent ep- epe epf epn epp epr ept ere erf ern erp err ert ete etf etn etp etr ett fee fef fen fep fer fet ffe fff ffn ffp ffr fft fne fnf fnn fnp fnr fnt fpe fpn fpp fpr fpt fre frf frn frp frr frt fte ftf ftn ftp ftr ftt ne- nee nef nen nep ner net nfe nff nfn nfp nfr nft nne nnf nnn nnp nnt npe npf npn npp npr npt nre nrf nrn nrp nrr nrt nte ntf ntn ntp ntr ntt p-p pee pef pen pep per pet pfe pff pfn pfp pfr pft pn- pne pnf pnn pnp pnr pnt ppe ppf ppn ppp ppr ppt pre prf prn prp prr prt pt- pte ptf ptn ptp ptr ptt re- ree ref ren rep rer ret rfe rff rfn rfp rfr rft rnn rnp rnr rnt rpe rpf rpn rpp rpr rpt rrf rrn rrp rrr rrt rte rtf rtn rtp rtr rtt te- tee tef ten tep ter tet tfe tff tfn tfp tfr tft tne tnf tnn tnp tnr tnt tpe tpf tpn tpp tpr tpt tre trf trn trp trr trt tte ttf ttn ttp ttr ttt