Problem C
Approval Area

The current policy of the government can be represented by a point in the plane. A voter’s ideal policy would also be represented by a point in the plane. The voter’s unhappiness with the current policy is measured by the distance between these two points. Many different distance metrics may be used, but we will use squared Euclidean distance here.

The voter’s unhappiness with the current policy is $u$. A new policy is proposed and is put to the vote.

The voter’s approval area is the set of points representing policies that the voter would be willing to vote for to replace the current policy. Determine the area of the voter’s approval area.

Input

The first and only line contains one integer $u$, where $0\le u\le 4\cdot {10}^{14}$.

Output

Output the area of the voter’s approval area. Your output is considered correct if it has at most a relative error of ${10}^{-9}$.

0

0E-100

3

9.424777960769379715387930149838508652591508198125317462924833776923449218858626995884104476026351204

400000000000000

1256637061435917.295385057353311801153678867759750042328389977836923126562514483599451213930136846827