URI 1002 problem is one the most simplest problem. Maybe for some beginners it take some time to understand the problem. If you are having some hard time solving it, here's the solution

Solution of URI - 1002 Area of a Circle in C

Input

The input contains a value of floating point (double precision).

Sample input :

100.64

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.

Sample output : 

A=31819.3103

Hope this will helps you <3