package tanxin;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;


class Pairmax implements Comparable<Pairmax>{
    int x;
    int y;

    public Pairmax(int x, int y) {
        super();
        this.x = x;
        this.y = y;
    }

    @Override
    public int compareTo(Pairmax p) {
        // TODO Auto-generated method stub
        return this.y-p.y>0?1:-1;
    }
}

public class 最大不相交区间数量 {

    /**
     * @param args
     * @throws IOException 
     */
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        int n=Integer.parseInt(bufferedReader.readLine());
        Pairmax x[]=new Pairmax[n];
        for(int i=0;i<n;i++){
            String p[]=bufferedReader.readLine().split(" ");
            int a=Integer.parseInt(p[0]);
            int b=Integer.parseInt(p[1]);
            x[i]=new Pairmax(a, b);
        }
        Arrays.sort(x);



        int res=0;
        int L=Integer.MIN_VALUE;
        int R=Integer.MIN_VALUE;

        for(int i=0;i<n;i++){
            if(x[i].x > R){
                R=x[i].y;
                res++;
            }
        }
        System.out.println(res);
    }

}