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.*;
import java.io.*;

public class  Restaurant
{
	static int n;
	public static void main(String[] args) throws IOException 
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		PrintWriter pw=new PrintWriter(System.out);

		int t=1;

		while(t-->0)
		{ 
			String str[]=br.readLine().trim().split(" ");
			n=Integer.parseInt(str[0]);

			//a=new Node[n];
			HashMap<Integer,Integer> mp=new HashMap<>();
			for(int i=0;i<n;i++)
			{
				str=br.readLine().trim().split(" ");
				int x=Integer.parseInt(str[0]);
				int y=Integer.parseInt(str[1]);

				//a[i]=new Node(x,y);

				if(mp.get(x)==null)
					mp.put(x,y);
				else 
					mp.put(x,Math.min(mp.get(x),y));
			}

			n=mp.size();
			int index=1;
			a=new Node[n+1];
			a[0]=new Node(0,0);
			for(Map.Entry entry:mp.entrySet())
			{
				int x=(int)entry.getKey();
				int y=(int)entry.getValue();
				a[index]=new Node(x,y);
				index++;
			}

			Comparator<Node> meet=new Comparator<Node>()
			{
				@Override
				public int compare(Node a,Node b)
				{
					return a.r-b.r;
				}
			};

			Arrays.sort(a,meet);
			/*pw.println();
			for(Node x:a)
				pw.println(x.l+" "+x.r);*/
			int count=0;
			int end=0;
			for(int i=1;i<n+1;i++)
			{
				if(a[i].l>end)
				{
					ans++;
					end=a[i].r;
				}
			}

			/*for(int x:dp)
				System.out.print(x+" ");
			System.out.println();*/

			pw.println(ans);
		}
		pw.flush();
	}

	

	static int ans=0;
	static Node a[];
	static class Node
	{
		int l;
		int r;
		public Node(int x,int y)
		{
			l=x;
			r=y;
		}
	}
	
}