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 C (Clang 10.0.0) (judge verdict: Accepted)

#include<stdio.h>
int main()
{
    int R;
    double circumference;
    scanf("%d",&R);
    if(1<= R && R<=100){
            circumference=2*3.1416*R;
            printf("%.2lf ",circumference);
    }
    return 0;
}