**Time limit:**1.00 s**Memory limit:**512 MB

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

Output:

2