import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main
{
    static Comparator<Node> cmp=new Comparator<Node>()
    {

        //按照右端点从小到大排序
        @Override
        public int compare(Node o1, Node o2)
        {
            return o1.r-o2.r;
        }
    };

    public static void main(String[] args)
    {
        Scanner scan=new Scanner(System.in);

        int n=scan.nextInt();
        Node[] nodes=new Node[n];
        for(int i=0;i<n;i++)
        {
            int l=scan.nextInt();
            int r=scan.nextInt();
            nodes[i]=new Node(l,r);
        }

        Arrays.sort(nodes,cmp);

        int cnt=0,ed=-2000000000;
        for(int i=0;i<n;i++)
        {
            if(nodes[i].l>ed)
            {
                cnt++;
                ed=nodes[i].r;
            }
        }

        System.out.println(cnt);
        scan.close();

    }

    private static class Node
    {
        private int l;
        private int r;
        public Node(int l,int r)
        {
            this.l=l;
            this.r=r;
        }
    }

}