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 C (GCC 5.4.1) (judge verdict: Runtime Error)

/*
# C++
clang++ -std=c++17 filename.cpp -o outname
# C
clang filename.c -o outname
*/

#ifdef __linux__
    #define gcd __gcd
#endif

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>

int main() {
    long long a, b, c, k;
    scanf("%d %d", a, b);
    c = (a+b)/2;
    if (abs(a-k) == abs(b-k)) {
        printf("&lld\n", c);
    } else {
        printf("IMPOSSIBLE\n");
    }
    return 0;
}