import java.util.*;

public class Program {
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();

        int[][] cars = new int[n][2];

        for(int i =0;i<n;i++){
            cars[i][0] = scan.nextInt();
            cars[i][0] = scan.nextInt();
        }

        Arrays.sort(cars, Comparator.comparingInt(pair -> pair[1]));

        int answer = 0;

        int right = cars[0][1];
        for (int i=1;i<n;i++){
            if (cars[i][0] > right){
                answer++;
                right = cars[i][1];
            }
        }

        System.out.println(answer);
    }
}