If $x=\frac{\sqrt{5}-\sqrt{4}}{\sqrt{5}+\sqrt{4}}$ and $y=\frac{\sqrt{5}+\sqrt{4}}{\sqrt{5}-\sqrt{4}}$ then the value of $\frac{x^2-x y+y^2}{x^2+x y+y^2}=$ ?

$\frac{361}{363}$ $\frac{341}{343}$ $\frac{384}{387}$ $\frac{321}{323}$

$\frac{321}{323}$