496. L-Shapes

Time limit per test: 0.75 second(s)
Memory limit: 262144 kilobytes
input: standard
output: standard

Let's say that two line segments of non-zero length form an if they are at a angle to each other and one endpoint of one segment coincides with one endpoint of the other.

There are N line segments on a plane. The segments are numbered from 1 to N. Count the number of distinct pairs of segments that form L-shapes. Two pairs are considered distinct if they contain segments with different numbers.

Input
The first line of the input line contains the integer N (1 ≤ N ≤ 5000). Each of the following N lines describes one segment and contains four integers x1, y1, x2, y2 ( ), where (x1, y1) and (x2, y2) are endpoints of the segment. It may be assumed that for each segment x1 ≠q x2 or y1 ≠q y2.

Output
The output file should contain a single integer, the total number of distinct pairs of line segments forming L-shapes.

Example(s)
 sample input sample output 7 0 4 0 7 4 4 1 6 1 6 -3 0 4 4 0 4 0 0 0 4 0 0 0 2 0 4 4 4  5 

Note. In the example the L-shapes are formed by the following pairs of segments: (1, 4), (1, 7), (2, 3), (4, 5), (5, 7). Note that the segments 4 and 7 coincide, but the pairs (1, 4) and (1, 7), for example, are still considered distinct. 