JaeHyeonKim19

import java.io.*;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringTokenizer;

public class Main {
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st;
		int n = Integer.parseInt(br.readLine());
		int [][] times = new int[n][2];
		for(int i = 0;i < n;i++) {
			st = new StringTokenizer(br.readLine());
			times[i][0] = Integer.parseInt(st.nextToken());
			times[i][1] = Integer.parseInt(st.nextToken());
		}
		Arrays.sort(times, (e1, e2) -> {
			if(e1[1] == e2[1]) {
				return Integer.compare(e1[0], e2[0]);
			}else {
				return Integer.compare(e1[1], e2[1]);
			}
		});
		int currentTime = 0;
		int count = 0;
		for(int i = 0;i < n;i++) {
			if(times[i][1] >= currentTime && times[i][0] >= currentTime) {
				currentTime = times[i][1];
				count++;
			}
		}
		System.out.print(count);
	}
}