Problem:
Score : 100 points

Problem Statement

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.

Constraints

1 \leq r \leq 100

r is an integer.

Input

Input is given from Standard Input in the following format:

r

Output

Print an integer representing the area of the regular dodecagon.

Sample Input 1

4

Sample Output 1

48

The area of the regular dodecagon is 3 \times 4^2 = 48.

Sample Input 2

15

Sample Output 2

675

Sample Input 3

80

Sample Output 3

19200

Solution in PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
$n = intval(trim(fgets(STDIN)));
for ($i = 0; $i < $n; ++$i) {
    $a[$i] = intval(trim(fgets(STDIN)));
    $b[$i] = $a[$i];
    $sai = max($a);
}
for ($i = 0; $i < $n; ++$i) {
    if ($sai > $a[$i])  {
        $max = $sai;
    } elseif ($sai == $a[$i]) {
        sort($b);
        $max = $b[1];
    }
    echo $max . PHP_EOL;
}

?>