-er eee eef eel eep eer ees eex ef- efe eff efi efl efp efr efs efx eie eif eii eil eip eir eis eix ele elf eli ell elp elr els elx ep- epe epf epi epl epp epr eps epx ere erf eri erl erp err ers es- ese esf esi esl esp esr ess esx ex- exe exi exl exp exr exs exx fee fef fei fel fep fer fes fex ffe fff ffi ffl ffp ffr ffs ffx fie fif fii fil fip fir fis fix fle flf fli fll flp flr fls flx fpe fpi fpl fpp fpr fps fpx fre frf fri frl frp frr frs fse fsf fsi fsl fsp fsr fss fsx fxe fxi fxp fxr fxs fxx i-f ie- iee ief iei iel iep ier ies iex ife iff ifi ifl ifp ifr ifs ifx iie iif iii iil iip iir iis iix il- ile ilf ili ill ilp ilr ils ilx ipe ipf ipi ipl ipp ipr ips ipx ir- ire irf iri irl irp irr irs irx is- ise isf isi isl isp isr iss ixe ixi ixl l-p lee lef lei lel lep ler les lex lfe lff lfi lfl lfp lfr lfs lfx lie lif lii lil lip lir lis lix lle llf lli lll llp llr lls lpe lpf lpi lpl lpp lpr lps lpx lrf lri lrp lrr lrs lse lsf lsi lsl lsp lsr lss lxi lxr lxx p-p pee pef pei pel pep per pes pex pfe pff pfi pfl pfp pfr pfs pfx pie pif pii pil pip pir pis pix ple plf pli pll plp plr pls plx ppe ppf ppi ppl ppp ppr pps ppx pre prf pri prl prp prr prs prx ps- pse psf psi psl psp psr pss psx pxe pxl pxr pxs re- ree ref rei rel rep rer res rex rfe rff rfi rfl rfp rfr rfs rie rif rii ril rip rir ris rix rle rlf rli rll rlp rlr rls rpe rpf rpi rpl rpp rpr rps rpx rrf rri rrl rrp rrr rrs rse rsf rsi rsl rsp rsr rss rsx rxp rxr rxs se- see sef sei sel sep ser ses sex sfe sff sfi sfl sfp sfr sfs sfx sie sif sii sil sip sir sis six sle slf sli sll slp slr sls slx spe spf spi spl spp spr sps spx sr- sre srf sri srl srp srr srs srx ss- sse ssf ssi ssl ssp ssr sss ssx sxi sxl sxs xee xel xep xer xes xex xfe xfl xfs xfx xie xii xis xix xlf xli xlr xls xpe xpf xpl xpp xps xrf xrx xsi xsl xsp xss xxi xxl xxp xxx