FENCE1  Build a Fence
There is a wall in your backyard. It is so long that you can’t see its endpoints. You want to build a fence of length L such that the area enclosed between the wall and the fence is maximized. The fence can be of arbitrary shape, but only its two endpoints may touch the wall.
Input
The input consists of several test cases.
For every test case, there is only one integer L (1<=L<=100), indicating the length of the fence.
The input ends with L=0.
Output
For each test case, output one line containing the largest area. Your answer should be rounded to 2 digits after the decimal point.
Example
Input: 1 0 Output: 0.16
hide comments
dhia01:
20190727 01:22:44
L^2/2*Phi 

toolatetostart:
20190617 13:03:22
@sarthak_1998 man don't mislead others due to u i got one wa,use pi=3.1415926536


abuhanif:
20190525 19:50:35
Taking ur advice about PI=3.142 i got WA @sharthak_1998


sarthak_1998:
20190330 12:06:34
Taking the value of pi=3.142 and not as pi=3.14159 cost me two WAs 

rollicks_7:
20190208 07:00:00
What is the use of such fence? 

anant6025:
20190207 21:53:04
Just one basic geometry concept and than its too easy to implement! 

flyer2403:
20190101 18:59:19
In python 3 use:


sandeep48:
20181227 04:23:45
once you get the logic problem is super easy


gokul27:
20181218 14:49:25
AC in one go!!


identity_1x:
20180909 16:04:43
Dedicated to those struggling in java ,try using DecimalFormat for rounding to proper value , printf for setting the precision and use pi = 3.14159 . :) 
Added by:  Fudan University Problem Setters 
Date:  20090523 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: C99 ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Fudan University Local Contest #1, practise session 