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.util.Arrays;
import java.util.Scanner;


public class B597 {

	class Pair implements Comparable<Pair>{
		int x; int y;
		
		public Pair(int x, int y) {
			this.x = x; this.y = y;
		}
		
		@Override
		public int compareTo(Pair o) {
			return this.y - o.y;
		}
	}
	
	public static void main(String[] args) {
		new B597().solve();
	}

	private void solve() {
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();
		Pair pair[] = new Pair[N];
		
		for (int i = 0; i < N; i++) {
			pair[i] = new Pair(sc.nextInt(), sc.nextInt());
		}
		
		Arrays.sort(pair);
		
		Pair prev = pair[0]; int numPairs = 1;
		
		for (int i = 1; i < N; i++) {
//			System.out.println(pair[i].x + " " + pair[i].y);
			if(pair[i].x > prev.y){
				numPairs++;
				prev = pair[i];
			}
		}
		System.out.println(numPairs);
		sc.close();
	}
	
}
