Circle Area

Version: Phuoc Hung OJ Extended

Problem Statement

Given the radius $r$ of a circle, compute its area $S=\pi r^2$. Use the Python 3 constant math.pi, not an arbitrary approximation such as $3.14$, and print exactly 6 decimal places.

Input

The only line contains real circle radius $r$.

Output

Print the circle area with exactly 6 decimal places.

Subtasks

• Subtask 1 (100 points): $r\ge0$.

Examples

Example 1

Input

1

Output

3.141593

Explanation. Substituting 1 into π × r² gives approximately 3.14159265359. The required output formatting produces 3.141593.

Example 2

Input

2.5

Output

19.634954

Explanation. Substituting 2.5 into π × r² gives approximately 19.6349540849. The required output formatting produces 19.634954.

Example 3

Input

0

Output

0.000000

Explanation. Substituting 0 into π × r² gives approximately 0. The required output formatting produces 0.000000.