A. Movie Festival
time limit per test
2 seconds
memory limit per test
1024 megabytes
input
standard input
output
standard output

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 $$$n$$$ ($$$1 \leq n \leq 2 \cdot 10^5$$$): the number of movies.

After this, there are $$$n$$$ lines that describe the movies. Each line has two integers $$$a$$$ and $$$b$$$ ($$$1 \leq a \leq b \leq 10^9$$$): the starting and ending times of a movie.

Output

Print one integer: the maximum number of movies.

Example
Input
3
3 5
4 9
5 8
Output
2