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.lang.*;

public class Rextester{
    public static void main(String[] args)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        int[][] array = new int[n][2];
        for(int i=0;i<n;i++){
            StringTokenizer st = new StringTokenizer(br.readLine());
            array[i][0]=Integer.parseInt(st.nextToken());
            array[i][1]=Integer.parseInt(st.nextToken());
        }
        br.close();
        Arrays.sort(array,(int[] a,int[] b)->{
            if(a[1]==b[1]){
                return a[0]-b[0];
            }
            return a[1]-b[1];
        });
        TreeMap<Integer,Integer> map = new TreeMap<Integer,Integer>();
        int max = 1;
        for(int i=0;i<n;i++){
            Integer z = map.lowerKey(array[i][0]);
            if(z==null){
                map.put(array[i][1],max);
            }
            else{
                int w = map.get(z)+1;
                max = Math.max(max,w);
                map.put(array[i][1],max);
            }
        }
        //printMap(map);
        System.out.println(max);
    }
    static void printMap(TreeMap<Integer,Integer> map){
        for(Map.Entry<Integer,Integer> mapElement:map.entrySet()){
            System.out.println(mapElement.getKey()+" "+mapElement.getValue());
        }
    }
}
            