Background

Luogu’s testdata is only for community communication and is not official testdata. Official judging link: https://www.cspro.org/.

Problem Description

On Xixi Aifu Island, there are $n$ fields scattered around. Each field can be viewed as a rectangular region on the Cartesian plane, uniquely determined by the bottom-left corner $(x_1, y_1)$ and the top-right corner $(x_2, y_2)$, with $x_1 < x_2$ and $y_1 < y_2$. Among these $n$ fields, the intersection area of any two fields is $0$; they may only overlap on their boundaries.

Recently, Dundun wants to reclaim a rectangular field of area $a \times b$ at the foot of Nanshan Mountain, with bottom-left corner $(0, 0)$ and top-right corner $(a, b)$. Compute the total area of the existing fields that lies within Dundun’s chosen region.

Input Format

Read input from standard input.

There are $n + 1$ lines in total.

The first line contains three positive integers $n$, $a$, and $b$ separated by spaces, representing the number of fields on Xixi Aifu Island and the coordinates of the top-right corner of Dundun’s chosen region.

The next $n$ lines each contain four integers $x_1$, $y_1$, $x_2$, and $y_2$ separated by spaces, describing the position of one field.

Output Format

Write output to standard output.

Output one integer, representing the area of fields within Dundun’s chosen region.

4 10 10
0 0 5 5
5 -2 15 3
8 8 15 15
-2 10 3 15

44

Hint

Sample Explanation

As shown in the figure, the area of fields within the chosen region (the green area) is $44$.

:::align{center} :::

Subtasks

All testdata satisfy $n \le 100$, and the absolute value of every input coordinate does not exceed $10^4$.

Translated by ChatGPT 5