The orbit of Venus is an ellipse with the sun as one focus. Placing the centre of the ellipse at the origin, an approximate equation for the orbit is $\frac{x^2}{5017}+\frac{y^2}{4970}=1$`x`25017+`y`24970=1, where $x$`x` and $y$`y` are measured in millions of miles.

Find the greatest possible distance across the ellipse. Round your answer to the nearest million miles.