Problem8808--[CSES Problem Set] Area of Rectangles

8808: [CSES Problem Set] Area of Rectangles

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Time Limit : 1.000 sec  Memory Limit : 512 MiB

Description

Given n rectangles, your task is to determine the total area of their union.

Input

The first input line has an integer n: the number of rectangles.
After that, there are n lines describing the rectangles. Each line has four integers $x_1, y_1, x_2$ and $y_2$: a rectangle begins at point $(x_1,y_1)$ and ends at point $(x_2,y_2)$.

Output

Print the total area covered by the rectangles.

Constraints

$1≤n≤10^5$
$-10^6≤x_1<x_2≤10^6$
$-10^6≤y_1<y_2≤10^6$

Sample 1 Input

3
1 3 4 5
3 1 7 4
5 3 8 6

Sample 1 Output

24

HINT

相同题目:CSES 1741

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