How do you simplify (sqrt 5 - 2)(sqrt 5 - 4)?

I found: $13 - 6 \sqrt{5}$
$\left(\sqrt{5} - 2\right) \left(\sqrt{5} - 4\right) = \sqrt{5} \sqrt{5} - 4 \sqrt{5} - 2 \sqrt{5} + 8 =$
$= 5 - 6 \sqrt{5} + 8 = 13 - 6 \sqrt{5}$