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

public class Back_1931 {
    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int N = Integer.parseInt(br.readLine());

        StringTokenizer st;
        int[][] arr = new int[N][2];

        for (int i = 0; i < N; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            arr[i][0] = Integer.parseInt(st.nextToken());   // 시작 시간
            arr[i][1] = Integer.parseInt(st.nextToken());   // 끝 시간
        }

        Arrays.sort(arr, new Comparator<int[]>() {
            @Override
            public int compare(int[] o1, int[] o2) {

                if (o1[1] == o2[1]) {
                    return o1[0] - o2[0];
                }
                return o1[1] - o2[1];
            }
        });

        int count = 0;
        int preTime = 0;

        for (int i = 0; i < N; i++) {
            if(preTime <= arr[i][0]){
                preTime = arr[i][1];
                count ++;
            }
        }
        System.out.println(count);
        br.close();
    }
}