Problem7508--[CSES Problem Set] Movie Festival

7508: [CSES Problem Set] Movie Festival

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Time Limit : 1.000 sec  Memory Limit : 256 MiB

Description

In a movie festival $n$ movies will be shown. 
You know the starting and ending time of each movie. 
What is the maximum number of movies you can watch entirely?

Input

The first input line has an integer $n$: the number of movies.
After this, there are $n$ lines that describe the movies. Each line has two integers $a$ and $b$: the starting and ending times of a movie.

Output

Print one integer: the maximum number of movies.

Constraints

$1 \leq n \leq 2 \times 10^5$
$1 \leq a < b \leq 10^9$

Sample 1 Input

3
3 5
4 9
5 8

Sample 1 Output

2

HINT

相同题目:CSES 1629

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