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.

Examples

Input

4


Output

48


Input

15


Output

675


Input

80


Output

19200
#include<iostream>
using namespace std;
int main(){
  int n; cin>>n;
  cout<<3*n*n<<"\n";
}