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.io.*;
import java.util.*;
import java.math.*;

public class TestingB {

    public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		PriorityQueue<Event> pq = new PriorityQueue<Event>(n, new EndTimeCompare());
		for(int i=0; i<n; i++){
			pq.add(new Event(in.nextInt(), in.nextInt()));	
		}
		//greedy algorithm works, keep taking the event that doesn't conflict with earliest end time
		int accepted = 0;
		int lastEndTime = 0;
		while(pq.size() != 0){
			Event e = pq.poll();
			if(e.startTime > lastEndTime){
				lastEndTime = e.endTime;
				accepted++;
			}
		}
		System.out.println(accepted);
	}
	
	private static class Event{
		int startTime;
		int endTime;
		
		public Event(int startTime, int endTime){
			this.startTime = startTime;
			this.endTime = endTime;
		}
	}
	
	private static class EndTimeCompare implements Comparator<Event>{
		public int compare(Event e1, Event e2){
			if(e1.endTime < e2.endTime)
				return -1;
			if(e1.endTime == e2.endTime)
				return 0;
			return 1;
		}
	}
}