#5568. CSES1740 交点
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CSES1740 交点
Intersection Points
Given n 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 line has an integer n: the number of line segments. Then there are n lines describing the line segments. Each line has four integers: x_1, y_1, x_2 and y_2: a line segment begins at point (x_1,y_1) and ends at point (x_2,y_2).
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