Intro

Today, I have begin the series of solving first 40 problems of URI Online Judge Beginner in python 3. This is problem number 1002 and 2nd post of this series. Let's dig in.

Description

Problem URL: https://www.urionlinejudge.com.br/judge/en/problems/view/1002

Input

The input contains a value of floating point (double precision), that is the variable R.

Output

Present the message "A=" followed by the value of the variable, as in the example bellow, with four places after the decimal point. Use all double precision variables. Like all the problems, don't forget to print the end of line after the result, otherwise you will receive "Presentation Error".

Samples Input

2.00
100.64
150.00

Samples Output

A=12.5664
A=31819.3103
A=70685.7750

*Note: Please always check the sample output how it's given, or you will get "Presentation Error", pretty annoying.

Understanding Problem

Pi is already given just formula of circle. pow() is a buildin function in the python if you want to use r*r no problem.