AE00  Rectangles
Byteman has a collection of N squares with side 1. How many different rectangles can he form using these squares?
Two rectangles are considered different if none of them can be rotated and moved to obtain the second one. During rectangle construction, Byteman can neither deform the squares nor put any squares upon any other ones.
Input
The first and only line of the standard input contains one integer N (1 <= N <= 10000).
Output
The first and only line of the standard output should contain a single integer equal to the number of different rectangles that Byteman can form using his squares.
Example
For the input data:
6
the correct result is:
8
Task author: Jakub Radoszewski.
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vritta:
20180329 18:05:56
Last edit: 20180329 21:16:11 

sarthak_8:
20180319 21:58:48
Cakewalk. Don't forget for n = 1, else WA :P 

badasshackme:
20180310 14:20:13
it took me 30 minutes to realize that YOU MUST NOT ADD NEW LINE SYMBOL AT THE END OF OUTPUT, OR YOUR ABSOLUTELY CORRECT RESULT WILL BE REPORTED AS WRONG. Sorry for caps, it is annoying when you solved problem mathematically and some random new line rule ruins it. 

pigpork:
20180308 13:47:40
AC IN ONE GO! 

richardks3647:
20180224 08:05:40
AC in one go! Last edit: 20180303 06:57:22 

dheerajdheeru:
20180222 02:42:11
AC in one go


goodwilllion:
20180129 09:21:37
AC IN ONE GO


sid_1097:
20180106 14:31:57
What should be the output for input 10000 and 20. 

hitesh87:
20171223 17:55:23
AC in one go!! 0.00s 

ajayc1007:
20171128 11:24:49
thanx iamgod96

Added by:  Race with time 
Date:  20090503 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Algorithmic Engagements 2009 