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 B597 {

	public static BufferedReader read = null;
	public static PrintWriter out = null;
	public static StringTokenizer token = null;
	
	
	public static void solve()
	{
		int n = nint();
		int[][] a = new int[n][2];
		for(int i=0; i<n; i++)
		{
			a[i][0] = nint();
			a[i][1] = nint();
		}
		Arrays.sort(a, new Comparator<int[]>(){
			public int compare(int[] a, int[] b)
			{
				return a[1]-b[1];
			}
		});
		int max = 1, cs = a[0][0], ce = a[0][1]; //pick the first order
		for(int i=1; i<n; i++)
		{
			if(a[i][0] > ce)
			{
				max++;
				cs = a[i][0];
				ce = a[i][1];
			}
		}
		out.println(max);
	}
	
	public static void main(String[] args)
	{
		read = new BufferedReader(new InputStreamReader(System.in));
		out = new PrintWriter(System.out);
		solve();
		out.flush();
		out.close();
		
	}
	
	// i/o functions
	public static String next() // returns the next string
	{
		while(token == null || !token.hasMoreTokens())
		{
			try {
				token = new StringTokenizer(read.readLine());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return token.nextToken();
	}
	
	public static int nint()
	{
		return Integer.parseInt(next());
	}
	public static long nlong()
	{
		return Long.parseLong(next());
	}
	public static double ndouble()
	{
		return Double.parseDouble(next());
	}
	public static int[] narr(int n)
	{
		int[] a = new int[n];
		for(int i=0; i<n; i++) a[i] = nint();
		return a;
	}
	
	public static long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i=0; i<n; i++) a[i] = nlong();
		return a;
	}
	
	
}


