Maximum Distance to the Fountain in a Semi-circular Park

In a semi-circular park with radius \(R\), a fountain is to be installed at the optimal position in order to minimize the maximum walking distance from any point on the park's boundary to the fountain. It can be shown that the optimal fountain placement is at the center of the full circle that the semi-circle is derived from. Under this positioning, the maximum distance from any point on the boundary to the fountain is given by \(R\sqrt{2}\).

Your task is to compute \(R\sqrt{2}\) for a given radius \(R\).

Note: The answer should be printed as a floating-point number with at least 6 digits after the decimal point.

inputFormat

The input consists of a single line containing one integer \(R\) (the radius of the semi-circular park).

outputFormat

Output a single floating-point number representing the maximum distance from any point on the boundary to the optimally placed fountain. The result should be computed as \(R\sqrt{2}\) and printed with a precision of at least 6 decimal places.

## sample

1

1.414213

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