Score : $100$ points
It is known that the area of a regular dodecagon inscribed in a circle of radius $a$ is $3a^2$.
Given an integer $r$, find the area of a regular dodecagon inscribed in a circle of radius $r$.
Input is given from Standard Input in the following format:
$r$
Print an integer representing the area of the regular dodecagon.
4
48
The area of the regular dodecagon is $3 \times 4^2 = 48$.
15
675
80
19200