#include<bits/stdc++.h>
using namespace std;
struct hd{
  int x,y;	
}a[1001];
bool cmp(hd c,hd d){
	return c.y<d.y;
}
int main(){
    int n,ans=1;
    cin>>n;
    for(int i=1;i<=n;i++){
    	cin>>a[i].x>>a[i].y;
    }
    sort(a+1,a+1+n,cmp);
    int ed=a[1].y;
    for(int i=2;i<=n;i++){
    	if(a[i].x>=ed){
    		ans++;
    		ed=a[i].y;
    	}
    }
    cout<<ans<<endl;
//for(int i=1;i<=n;i++){
//	cout<<a[i].x<<" "<<a[i].y<<endl;
//}
	return 0;
}
/**************************************************************
	Problem: 1372
	User: zengdongxin
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2084 kb
****************************************************************/