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: Wrong Answer)

#include<stdio.h>
int main(void){
  int X,Y,Z,T;
  scanf("%d",&X);
  scanf("%d",&Y);
  scanf("%d",&Z);
  T = X;
  X = Y;
  Y = T;
  T = Z;
  Z = X;
  X = T;
  printf("%d",X);
  printf("%d",Y);
  printf("%d",Z);
  return 0;
}