import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
 
public class Main {
 
    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(bf.readLine());
        Time[] times = new Time[n];
        StringTokenizer st;
 
        for(int i = 0 ;i<n;i++){
            st = new StringTokenizer(bf.readLine());
            times[i] = new Time(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
        }
 
        Arrays.stream(times).sorted(Comparator.comparing(o -> o.end));//끝난 시간 기준으로 오름차순 정렬
 
        int count = (times.length == 0) ? 0:1;
 
        int j=0;
        for(int i=1; i<times.length;i++){
            if(times[j].end<=times[i].start){// 시작 시간이 끝난 시간보다 같거나 크면
                count++;
                j=i;
            }
        }
        System.out.println(count);
    }
static class Time{
    int start;
    int end;
 
    public Time(int start, int end) {
        this.start = start;
        this.end = end;
    }
  }
}
 
 

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MgoyIDIKMSAyCg==

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