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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mriow:
20190809 09:07:30
O(sqrt(n)) with a quite straighfoward solution using the picture provided. 

king_25:
20190730 12:09:37
AC,Hint:find factors. Last edit: 20190730 12:12:14 

rikilg:
20190719 13:59:52
AC in one go! 

rohan_rocksss:
20190602 11:26:24
AC in one go. O(n*log(n)) solution. Last edit: 20190602 11:28:18 

hetp111:
20190411 16:59:34
did it in O(n*sqrt(n))... =( 

alfeberlin:
20190404 13:15:10
See also https://oeis.org/A094820


harish_49:
20190322 06:51:49
AC in 2 go ! haha @sqrt(n) 

rahulrawat09:
20190320 16:45:20
for(int i=1;i<=sqrt(n);i++)


souravramos04:
20190222 15:23:15
Don't forget to initialize your count to 0. AC on 6th attempt. 

akash1234:
20190105 13:21:38
Ac in one go 
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 