-er eee eef eek eel eep eer eex ef- efe eff efi efl efp efr efx eie eif eii eik eil eip eir eix eke ekf eki ekl ekp ekr ele elf eli elk ell elp elr elx ep- epe epf epi epl epp epr epx ere erf eri erk erl erp err ex- exe exi exl exp exr exx fee fef fei fek fel fep fer fex ffe fff ffi ffk ffl ffp ffr ffx fie fif fii fik fil fip fir fix fkf fki fkk fkl fkp fle flf fli fll flp flr flx fpe fpi fpk fpl fpp fpr fpx fre frf fri frk frl frp frr fxe fxi fxp fxr fxx i-f ie- iee ief iei iek iel iep ier iex ife iff ifi ifl ifp ifr ifx iie iif iii iil iip iir iix ike ikf iki ikk ikl ikr ikx il- ile ilf ili ilk ill ilp ilr ilx ipe ipf ipi ipl ipp ipr ipx ir- ire irf iri irk irl irp irr irx ixe ixi ixl ke- kee kef kei kek kel kep ker kex kff kfi kfx kie kif kii kik kil kip kir kix kke kki kkk kkl kkp kkr kl- klf kli klr klx kpe kpf kpi kpk kpl kpp kpr krf kri krk krl krp krr kxl l-p lee lef lei lek lel lep ler lex lfe lff lfi lfk lfl lfp lfr lfx lie lif lii lik lil lip lir lix lkl lkp lkr lle llf lli llk lll llp llr lpe lpf lpi lpk lpl lpp lpr lpx lrf lri lrk lrp lrr lxi lxr lxx p-p pee pef pei pek pel pep per pex pfe pff pfi pfk pfl pfp pfr pfx pie pif pii pik pil pip pir pix pke pkf pki pkl pkp pkr ple plf pli plk pll plp plr plx ppe ppf ppi ppk ppl ppp ppr ppx pre prf pri prk prl prp prr prx pxe pxk pxl pxr re- ree ref rei rek rel rep rer rex rfe rff rfi rfk rfl rfp rfr rie rif rii rik ril rip rir rix rke rkf rkk rkp rle rlf rli rll rlp rlr rpe rpf rpi rpk rpl rpp rpr rpx rrf rri rrk rrl rrp rrr rxp rxr xee xel xep xer xex xfe xfl xfx xie xii xix xke xkl xlf xli xlr xpe xpf xpl xpp xrf xrx xxi xxl xxp xxx