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 Ruby (2.3.3) (judge verdict: Accepted)


# describe Abc134A do
#   context 'test' do
#     it 'sample' do
#       expect(Abc134A.calc(4)).to be(48)
#       expect(Abc134A.calc(15)).to be(675)
#       expect(Abc134A.calc(80)).to be(19200)
#     end
#   end
# end

class Abc134A
  def self.input()
    password_string = STDIN.gets.to_i
  end

  def self.output(result)
    puts result
  end

  def self.calc(r)
    3 * r * r
  end

  def self.main()
    r = input()
    result = calc(r)
    output(result)
  end
end

if __FILE__ == $0
  Abc134A.main
  exit
end