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 \le n \le 2 \cdot 10^5~
• ~1 \le a < b \le 10^9~

Example Input

3
3 5
4 9
5 8

Example Output

2