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)

/*
 *Author - Abhas Jain
 */
 
#include <bits/stdc++.h>
 
#define F first
#define S second
#define all(c) c.begin(), c.end()
#define endl '\n'
#define pb push_back
 
 
typedef long long ll;
typedef long double ld;
 
using namespace std;
mt19937 rang(chrono::high_resolution_clock::now().time_since_epoch().count());
 
const ld PI = 3.141592653589793;
const ll INF = 9223372036854775807ll;
const ll mod = 1e9 + 7;
 
void solve() 
{
    int r;
    cin >> r;
    cout << 3 * r * r << endl;
}
 
int main( )
{   
    ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    srand(chrono::high_resolution_clock::now().time_since_epoch().count());
    solve();
    return 0;
}