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)

b = gets.to_i
# s = gets.chomp
# s,t = gets.split.map(&:to_s)
# r= gets.split.map(&:to_i)

# s = gets.chomp.chars.uniq
# puts gets.chomp.chars.uniq.size != 1 ? "Yes" : "No"
# r = a-b
p 3*(b**2)