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++14 (GCC 5.4.1) (judge verdict: Accepted)

/*  Name: Abu Hurayra
    Handle: HurayraIIT
    Institute: IIT_JU   */

#include <bits/stdc++.h>
using namespace std;

typedef long long LL;
typedef string S;
typedef double D;
typedef vector<int> vi;
typedef queue<int> qi;
typedef stack<int> si;

#define pi acos(-1.0)
#define endl '\n'
#define off ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define Fin freopen("input.txt","r",stdin)
#define Fout freopen("output.txt","w",stdout)

int main()
{
	off;
    int n;
    cin >> n;
    cout << 3*n*n << endl;
    


	return 0;

}