Old MacDonald had a farm, and on that farm she had a square-shaped pasture, and on that pasture she had a cow that was prone to escape. So now Old MacDonald wants to set up a fence around the pasture. Given the area of the pasture, how long a fence does Old MacDonald need to buy? 

-----Input-----
The input consists of a single integer $a$ ($1 \le a \le 10^{18}$), the area in square meters of Old MacDonald’s pasture.

-----Output-----
Output the total length of fence needed for the pasture, in meters. The length should be accurate to an absolute or relative error of at most $10^{-6}$.

-----Examples-----
Sample Input:
16
Sample Output:
16

Difficulty: introductory

Starter code:

Solutions: