Cone Volume

Version: Phuoc Hung OJ Extended

Problem Statement

A right circular cone has base radius $r$ and height $h$. Its volume is $V=\dfrac{\pi r^2h}{3}$. Use Python 3 math.pi and print exactly 4 decimal places.

Input

The only line contains real base radius $r$ and height $h$ of the cone.

Output

Print cone volume $V$ with exactly 4 decimal places.

Subtasks

• Subtask 1 (100 points): $r,h\ge0$.

Examples

Example 1

Input

1 3

Output

3.1416

Explanation. Substituting 1, 3 into π × r² × h / 3 gives approximately 3.14159265359. The required output formatting produces 3.1416.

Example 2

Input

2 6

Output

25.1327

Explanation. Substituting 2, 6 into π × r² × h / 3 gives approximately 25.1327412287. The required output formatting produces 25.1327.

Example 3

Input

0.5 1.5

Output

0.3927

Explanation. Substituting 0.5, 1.5 into π × r² × h / 3 gives approximately 0.392699081699. The required output formatting produces 0.3927.