-er eee eef eem eep eer ees eex ef- efe eff efi efm efp efr efs efx eie eif eii eim eip eir eis eix em- eme emf emi emm emp emr ems emx ep- epe epf epi epm epp epr eps epx ere erf eri erm erp err ers es- ese esf esi esm esp esr ess esx ex- exe exi exp exr exs exx fee fef fei fem fep fer fes fex ffe fff ffi ffm ffp ffr ffs ffx fie fif fii fim fip fir fis fix fme fmf fmi fmm fmp fmr fms fmx fpe fpi fpm fpp fpr fps fpx fre frf fri frm frp frr frs fse fsf fsi fsm fsp fsr fss fsx fxe fxi fxm fxp fxr fxs fxx i-f ie- iee ief iei iem iep ier ies iex ife iff ifi ifm ifp ifr ifs ifx iie iif iii iim iip iir iis iix im- ime imf imi imm imp ims imx ipe ipf ipi ipm ipp ipr ips ipx ir- ire irf iri irm irp irr irs irx is- ise isf isi ism isp isr iss ixe ixi m-f m-r mee mef mei mem mep mer mes mex mfe mff mfi mfm mfp mfr mfs mi- mie mif mii mim mip mir mis mix mme mmf mmi mmm mmp mmr mms mmx mpe mpf mpi mpm mpp mpr mps mpx mre mrf mri mrm mrp mrr mrs mrx mse msf msi msm msp msr mss msx mxi mxp mxr mxs p-p pee pef pei pem pep per pes pex pfe pff pfi pfm pfp pfr pfs pfx pie pif pii pim pip pir pis pix pme pmf pmi pmm pmp pmr pms pmx ppe ppf ppi ppm ppp ppr pps ppx pre prf pri prm prp prr prs prx ps- pse psf psi psm psp psr pss psx pxe pxm pxr pxs re- ree ref rei rem rep rer res rex rfe rff rfi rfm rfp rfr rfs rie rif rii rim rip rir ris rix rme rmf rmi rmm rmp rmr rms rmx rpe rpf rpi rpm rpp rpr rps rpx rrf rri rrm rrp rrr rrs rse rsf rsi rsm rsp rsr rss rsx rxp rxr rxs se- see sef sei sem sep ser ses sex sfe sff sfi sfm sfp sfr sfs sfx sie sif sii sim sip sir sis six sme smf smi smm smp smr sms smx spe spf spi spm spp spr sps spx sr- sre srf sri srm srp srr srs srx ss- sse ssf ssi ssm ssp ssr sss ssx sxi sxm sxs xee xem xep xer xes xex xfe xfm xfs xfx xie xii xis xix xmf xmi xmm xmp xmr xms xmx xpe xpf xpm xpp xps xrf xrx xsi xsm xsp xss xxi xxp xxx