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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.List;
import java.util.Scanner;

public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

	    int r=gi();

	   
	    System.out.print(3*r*r);

//        if ((x.charAt(0)==x.charAt(1) && x.charAt(2)==x.charAt(3) && x.charAt(0)!=x.charAt(2))
//        || (x.charAt(0)==x.charAt(2) && x.charAt(1)==x.charAt(3) && x.charAt(0)!=x.charAt(1))
//        || (x.charAt(0)==x.charAt(3) && x.charAt(2)==x.charAt(1) && x.charAt(0)!=x.charAt(2))) {
//        	System.out.print("Yes");
//        }else {
//        	System.out.print("No");
//        }


	}
	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
}