Module: (C++) Real numbers

Problem

Write a program that calculates the length of a circle through the area of the circle.


The circle length from the known area of the circle can be calculated by the formula :
\(L=\sqrt{S4\pi}\) ,
\(\pi\) - number of pi;
\(S\) - area of the circle.

You can use built-in constants to get the exact value of pi.
In C++ you must write the following line at the beginning of your program
#define _USE_MATH_DEFINES

In Python, you can use a constant from the math library math.pi


Input format
Given an one real number - area of the circle S (1 <= S <= 10³).

Output format
Output the circle length.
 

Example

N	Input	Output
1	5.0	7.926654595212022