Practice on Toph

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Pie Are Squared

Limits 1s, 512 MB

Given the radius of a circle, calculate and print its area.

The area of a circle can be computed using the following formula:

$ A = \pi r^2 $

For pi, you can use 3.141592653589793, or acos(-1).

Input

The input will contain one floating point number r (r < 2000).

Output

Print the area of the circle (accurate to 10-4).

Samples

InputOutput
2
12.5663706144

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