import java.io.*;
import java.util.*;

class seg {
    int l, r;
    seg(int l, int r) {
        this.l = l;
        this.r = r;
    }
}

class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));

        int n = Integer.parseInt(in.readLine());
        seg[] segs = new seg[n]; // 只创建 n 个 seg 对象

        for (int i = 0; i < n; i++) {
            String[] arr = in.readLine().split(" ");
            int l = Integer.parseInt(arr[0]);
            int r = Integer.parseInt(arr[1]);
            segs[i] = new seg(l, r);
        }

        Arrays.sort(segs, (a, b) -> a.r - b.r); //全局变量创建segs会报错，因为不能排序null

        int res = 0;
        int end = Integer.MIN_VALUE;

        for (int i = 0; i < n; i++) {
            seg cur = segs[i];
            if (end < cur.l) {
                res++;
                end = cur.r;
            }
        }

        out.write(res + ""); // 输出结果并换行
        in.close();
        out.flush();
        out.close();
    }
}