SUMFOUR  4 values whose sum is 0
The SUM problem can be formulated as follows: given four lists A, B, C, D of integer values, compute how many quadruplet (a, b, c, d ) belongs to A x B x C x D are such that a + b + c + d = 0 . In the following, we assume that all lists have the same size n
Input
The first line of the input file contains the size of the lists n (this value can be as large as 4000). We then have n lines containing four integer values (with absolute value as large as 2^{28} ) that belong respectively to A, B, C and D .
(Edited: n <= 2500)
Output
Output should be printed on a single line.
Example
Input: 6 45 22 42 16 41 27 56 30 36 53 37 77 36 30 75 46 26 38 10 62 32 54 6 45 Output: 5
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xxbloodysantaxx:
20150608 20:48:58
Time Limit is too strict will make you cry! 

kirakira:
20150608 04:53:20
damn i almost cry for not AC such "easy" problem :(


i_am_looser:
20150508 15:19:09
STL  took 5 minute to get AC : ) 

Lehar:
20150412 17:51:25
Damn! Finally AC! :D 

lucky:
20150329 10:56:43
O(n^2 *logn) is giving me a TLE why????? is der any better method Last edit: 20150329 10:57:10 

Noureldin Yosri:
20150311 20:51:09
O(n^2 log(n)) + optimization


Kishlay Raj:
20150201 09:42:35
3


Rajat (1307086):
20150131 01:42:23
Lot of optimization needed. 

kailash:
20150120 07:35:33
@Chandan Mittal if you have used cin and cout , try using printf and scanf 

Chandan Mittal:
20150108 23:56:49
O(n^2 * log(n)) gives TLE. But why??? :( 
Added by:  Abhilash I 
Date:  20070206 
Time limit:  1.419s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  South western 0506 