-er eee eef eek eep eer eet ef- efe eff efp efr eft eke ekf ekp ekr ekt ep- epe epf epp epr ept ere erf erk erp err ert ete etf etk etp etr ett fee fef fek fep fer fet ffe fff ffk ffp ffr fft fkf fkk fkp fkt fpe fpk fpp fpr fpt fre frf frk frp frr frt fte ftf ftk ftp ftr ftt k-t ke- kee kef kek kep ker ket kff kke kkk kkp kkr kkt kpe kpf kpk kpp kpr kpt krf krk krp krr krt kte ktf ktk ktp ktr ktt p-p pee pef pek pep per pet pfe pff pfk pfp pfr pft pke pkf pkp pkr pkt ppe ppf ppk ppp ppr ppt pre prf prk prp prr prt pt- pte ptf ptk ptp ptr ptt re- ree ref rek rep rer ret rfe rff rfk rfp rfr rft rke rkf rkk rkp rkt rpe rpf rpk rpp rpr rpt rrf rrk rrp rrr rrt rte rtf rtk rtp rtr rtt te- tee tef tek tep ter tet tfe tff tfk tfp tfr tft tke tkk tkp tkr tkt tpe tpf tpk tpp tpr tpt tre trf trk trp trr trt tte ttf ttk ttp ttr ttt