-er eee eef eeg eep eer eex ef- efe eff efg efp efr efx ege egf egg egp egr egx ep- epe epf epg epp epr epx ere erf erg erp err ex- exe exp exr exx fee fef feg fep fer fex ffe fff ffg ffp ffr ffx fge fgf fgg fgp fgr fpe fpg fpp fpr fpx fre frf frg frp frr fxe fxg fxp fxr fxx g-p ge- gee gef geg gep ger gex gfe gff gfp gfr gfx ggg ggp ggr gpe gpf gpg gpp gpr gpx gre grf grg grp grr grx gxf gxp p-p pee pef peg pep per pex pfe pff pfg pfp pfr pfx pge pgf pgg pgp pgr ppe ppf ppg ppp ppr ppx pre prf prg prp prr prx pxe pxg pxr re- ree ref reg rep rer rex rfe rff rfg rfp rfr rge rgf rgg rgp rgr rgx rpe rpf rpg rpp rpr rpx rrf rrg rrp rrr rxp rxr xee xeg xep xer xex xfe xfx xge xgp xpe xpf xpg xpp xrf xrx xxp xxx