You are provided with the radius of a circle "A". Find the length of its circumference.
Note: In case the output is coming in decimal, roundoff to 2nd decimal place. In case the input is a negative number, print "Error".
Input Description:
The Radius of a circle is provided as the input of the program.
Output Description:
Calculate and print the Circumference of the circle corresponding to the input radius up to two decimal places.
Sample Input :
2
Sample Output :
12.57