#include<bits/stdc++.h>
using namespace std;
struct wsl{
	int x,y;
}a[200];
bool cmp(wsl c,wsl d){
	return c.y<d.y;
}
int main(){
	int n;
	cin>>n; 
	for(int i=1;i<=n;i++){
		cin>>a[i].x>>a[i].y;
	}
	sort(a+1,a+1+n,cmp);
	int ans=1,e=a[1].y;
	for(int i=2;i<=n;i++){
		if(a[i].x>e){
			ans++;
			e=a[i].y;
		}
	}
	cout<<ans;

	return 0;
}

/**************************************************************
	Problem: 1372
	User: laichenxu
	Language: C++
	Result: Wrong Answer
****************************************************************/