- Time limit: 1.00 s
- Memory limit: 512 MB
Given horizontal and vertical line segments, your task is to calculate the number of their intersection points.
You can assume that no parallel line segments intersect, and no endpoint of a line segment is an intersection point.
Input
The first input line has an integer : the number of line segments.
Then there are lines describing the line segments. Each line has four integers: , , and : a line segment begins at point and ends at point .
Output
Print the number of intersection points.
Constraints
Example
Input:
3 2 3 7 3 3 1 3 5 6 2 6 6
Output:
2