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

• \(1 \leq n \leq 2 \cdot 10^5\)
• \(1 \leq a < b \leq 10^9\)

Example

Sample input

3  
3 5  
4 9  
5 8

Sample output

2