There are some 2D coordinates on the Cartesian plane. Please count all the possible acute triangles whose inner angles are all smaller than 90 degrees on the plane. For example, if there are five dots on the plane whose coordinate are p1 (1, 1), p2 (3, 1), p3 (2, 3), p4 (2, 4) and p5 (4, 4), there are three acute triangles on the plane which are p1-p2-p3, p1-p2-p4, and p2-p4-p5.
The input consists of several test cases. In each test case, the first line is an integer indicating N points on the Cartesian plane. ( 0 < N < 300 ) In the next N lines, there are two integers in each line. And all the integers are ranged from -10000 to 10000. You can assume that no three points will be collinear. When N equals to 0, the input file ends.
Print the total number of the acute triangles in a newline.