Problem:
Score : 100 points

Problem Statement

Print the circumference of a circle of radius R.

Constraints

1 \leq R \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

R

Output

Print the circumference of the circle.
Your output is considered correct if and only if its absolute or relative error from our answer is at most 10^{-2}.

Sample Input 1

1

Sample Output 1

6.28318530717958623200

Since we accept an absolute or relative error of at most 10^{-2}, 6.28 is also an acceptable output, but 6 is not.

Sample Input 2

73

Sample Output 2

458.67252742410977361942

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.*;
class  Main
{
    public static void main (String[] args) 
    {
       Scanner sc =new Scanner(System.in); 
       System.out.println();
       int r=sc.nextInt();
       double c=0.0d;
       c=2*3.14*r;
       System.out.println(c);
       
    }
}