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Convex

Time Limit: 10000/4000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2474    Accepted Submission(s): 844


Problem Description
Your task is very simple. You will get the coordinates of n points in a plane. It is guaranteed that there are no three points on a straight line. You can choose any four points from these points to construct a quadrangle. Now, please tell me how many convex quadrangles you can construct.
 

Input
The first line of input contain an integer z (z ¡Ü 20), indicating the number of test cases.
For each test case, the first line contain an integer n (4 ¡Ü n ¡Ü 700), indicating the number of points. Each of the next n lines contains two integers x and y (-1000000 ¡Ü x, y ¡Ü 1000000), indicating the coordinate of corresponding point.

 

Output
For each test case, just output a single integer, the number of convex quadrangles you can construct.
 

Sample Input
2 4 0 0 0 1 1 0 1 1 4 0 0 1 0 0 1 -1 -1
 

Sample Output
1 0
 

Source
 

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