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.

Input

Input is given from Standard Input in the following format:
r

Output

Print an integer representing the area of the regular dodecagon.

Constraints

• $1 \leq r \leq 100$
• r is an integer.

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

见题面 Input 部分

见题面 Output 部分