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.IOException;
import java.util.HashMap;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.TreeMap;

public final class Main
{
	public static void main(String args[]) throws IOException
	{
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();

		TreeMap<Integer, Integer> orders = new TreeMap<>();
		for (int i = 0; i < n; i++)
		{
			int s = in.nextInt();
			int e = in.nextInt();
			if (orders.get(s) == null) orders.put(s, e);
			else if (orders.get(s) > e) orders.put(s, e);
		}

		HashMap<Integer, Integer> max = new HashMap<>();
		int currentMax = 0;
		for (Entry<Integer, Integer> entry : orders.descendingMap().entrySet())
		{
			int s = entry.getKey();
			int e = entry.getValue();
			Integer key = orders.ceilingKey(e + 1);
			int res;
			if (key == null) res = 1;
			else res = max.get(key) + 1;
			currentMax = Math.max(res, currentMax);
			max.put(s, currentMax);
		}
		System.out.println(currentMax);
	}
}
