SPOJ Problem Set (classical)
1296. 4 values whose sum is 0
Problem code: SUMFOUR

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 .
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
