Rectangles and nails#1363
On the coordinate plane, you are given rectangles, each specified by a pair of opposite vertices. The sides of the rectangles are parallel to the coordinate axes, and the coordinates of the vertices are integers from the interval . What is the maximal number of rectangles that can be nailed to the plane with a single nail? A rectangle is considered nailed if the nail is hammered into an interior point of the rectangle.
The first line contains one integer .
Each of the next lines contains integers—the coordinates of one of the diagonals of a rectangle.
Output a single integer—the largest number of rectangles that can be nailed with one nail.
Example 1