Rectangular window#5955

Rectangular window

2 seconds
256 megabytes
Hard

Consider a family of rectangles, each with a perimeter of . Determine the rectangle with the smallest area that can encompass any rectangle from this family.

Input

An integer (1 \leq P \leq 1000).

Output

Output a single real number — the area of the smallest rectangle, with an absolute or relative error of no more than 10^{-8}.

Examples

Example 1

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