-ey eee eef eet eex eey ef- efe eff efi eft efx eie eif eii eit eix ete etf eti ett etx ety ex- exe exi ext exx exy eye eyt fee fef fei fet fex fey ffe fff ffi fft ffx ffy fie fif fii fit fix fte ftf fti ftt ftx fty fxe fxi fxt fxx fy- fye fyi i-f ie- iee ief iei iet iex iey ife iff ifi ift ifx ify iie iif iii iit iix ite itf iti itt itx ity ixe ixi ixy iye iyt iyy t-x te- tee tef tei tet tex tey tfe tff tfi tft tfx tie tif tii tit tix tiy tte ttf tti ttt ttx tty txe txf txi txt tye tyf tyt xee xet xex xfe xft xfx xie xii xit xix xtf xti xtx xty xxi xxx xxy xyy yee yef yei yet yex yey yfe yff yft yie yif yii yit yte ytf ytt yxe yxy yye yyf yyt yyy