Properties of Matter Part 2

A uniform heavy rod of mass 20‌kg, cross sectional area 0.4m2 and length 20m is hanging from a fixed support. Neglecting the lateral contraction, the elongation in the rod due to its own weight is x×10−9m. The value of x is ________.
(Given, young modulus Y=2×1011Nm−2 and g=10ms−2 )