A restaurant received n orders for the rental. Each rental order reserve the restaurant for a continuous period of time, the i-th order is characterized by two time values — the start time li and the finish time ri (li ≤ ri).

Restaurant management can accept and reject orders. What is the maximal number of orders the restaurant can accept?

No two accepted orders can intersect, i.e. they can't share even a moment of time. If one order ends in the moment other starts, they can't be accepted both.

Input

The first line contains integer number n (1 ≤ n ≤ 5·105) — number of orders. The following n lines contain integer values li and ri each (1 ≤ li ≤ ri ≤ 109).

Output

Print the maximal number of orders that can be accepted.

Examples

Input

2
7 11
4 7


Output

1


Input

5
1 2
2 3
3 4
4 5
5 6


Output

3


Input

6
4 8
1 5
4 7
2 5
1 3
6 8


Output

2
import java.awt.Point;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;


public class Tree {
	

	public static void main(String[] args) {
		
		Scanner in = new Scanner(System.in);
		
		
		int n = in.nextInt();
		
		List<Point> list = new ArrayList<>();
		
		for(int i=0; i<n; i++) {
			list.add(new Point(in.nextInt(), in.nextInt()));
		}
		
		Collections.sort(list, new Comparator<Point>() {

			@Override
			public int compare(Point o1, Point o2) {
				return o1.y - o2.y;
			}
		});
		
		int pick = 0;
		int last = -1;
		int cur = 0;
		while(true) {
			
			if(cur == n)
				break;
			Point now = list.get(cur);
			
			if(now.x > last) {
				pick++;
				last = now.y;
			}
			
			cur++;
		}
		
		System.out.println(pick);
		
	
		
	}
}

