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
devmayukh: 2019-11-24 10:44:49

Why are you defining Pi yourself? There is M_PI in <math.h> in C/C++, and Math.PI in Java.

quannguyenlhp: 2019-08-12 13:58:05

Use pi = 3.14 got WA, use pi = 3.141592654 and AC.

dhia01: 2019-07-27 01:22:44

L^2/2*Phi

toolatetostart: 2019-06-17 13:03:22

@sarthak_1998 man don't mislead others due to u i got one wa,use pi=3.1415926536

abuhanif: 2019-05-25 19:50:35

Taking ur advice about PI=3.142 i got WA @sharthak_1998
Then used PI=2*acos(0.0) and AC

sarthak_1998: 2019-03-30 12:06:34

Taking the value of pi=3.142 and not as pi=3.14159 cost me two WAs

rollicks_7: 2019-02-08 07:00:00

What is the use of such fence?

anant6025: 2019-02-07 21:53:04

Just one basic geometry concept and than its too easy to implement!

flyer2403: 2019-01-01 18:59:19

In python 3 use:
print("{0:.2f}".format(l*l/(2*pi)))
Instead of:
print(round(l*l/(2*pi),2));

sandeep48: 2018-12-27 04:23:45

once you get the logic problem is super easy
ac in one go


Added by:Fudan University Problem Setters
Date:2009-05-23
Time limit:0.25s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: C99 ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:Fudan University Local Contest #1, practise session