Given 

Reaction	Energy change (in Kj)
$Li\left(s\right)\to Li\left(g\right)$	161
$Li\left(g\right)\to L{i}^{+}\left(g\right)$	520
$\frac{1}{2}{F}_2\left(g\right)\to F\left(g\right)$	77
$F\left(g\right)+e^{-}\to F^{-}\left(g\right)$	(Electron gain enthalpy)
$L{i}^{+}\left(g\right)+F^{-}\left(g\right)\to LiF\left(s\right)$	-1047
$Li\left(s\right)+\frac{1}{2}{F}_2\left(g\right)\to LiF\left(s\right)$	-617
Based on data provided, the value of electron gain enthalpy of fluorine would be $-xkjmo{l}^{-1}$. X value