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.*;
public class Main {

	public static final int mod=1000000007;	
	static long[][] dp;
	public static void main(String[] args) throws IOException {
		
		//File filein = new File("input.txt");
		//BufferedReader sc=new BufferedReader(new FileReader(filein));
		//PrintWriter out=new PrintWriter(new FileWriter("output.txt"));		

		//Scanner sc=new Scanner(System.in);
		BufferedReader sc=new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out=new PrintWriter(System.out);		
		//int tt=Integer.parseInt(sc.readLine());
		int t=1;
		while(t-->0){
			out.flush();
			String[] ip=sc.readLine().split(" ");
			int n=Integer.parseInt(ip[0]);			
			int[][] arr=new int[n][2];
			for(int i=0;i<n;i++){
				ip=sc.readLine().split(" ");
				arr[i][0]=Integer.parseInt(ip[0]);
				arr[i][1]=Integer.parseInt(ip[1]);
			}
			Arrays.sort(arr,(a,b)->Integer.compare(a[1], b[1]));
			
			int currf=-1;
			int ans=0;
			for(int i=0;i<n;i++){
				int start=arr[i][0];
				int finish=arr[i][1];
				if(start>currf){
					ans++;
					currf=finish;
				}
			}
			out.println(ans);

		}
		out.flush();
		out.close();
		sc.close();
	}

	

}