Tricky Ratio

Given the radius ($r$) of a circle you have to calculate the ratio between the circumference ($C$) of the circle and its diameter ($d$).

The circumference of a circle is its enclosing boundary. It is calculated as $C = 2 \pi r$.

The diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circumference of the circle.

For this problem, you have to calculate the ratio $C:d$. You have to print the answer accurate to 5 decimal places.

Input

The input will contain a single floating point number $r$ ($0 < r < 100$).

Output

Print the ratio $C:d$ as a floating point number accurate to 5 decimal places.

Sample

Input	Output
3	3.14159