#include<bits/stdc++.h>
using namespace std;
struct Node{
	int x;
	int y;
}a[101];
bool cmp(Node c,Node d){	
	return c.y<d.y;
}
int n,end,ans=1;
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i].x>>a[i].y;
	}
	sort(a+1,a+n+1,cmp);
//	for(int i=1;i<=n;i++){
//		cout<<a[i].x<<' '<<a[i].y<<endl;
//	}
	end=a[1].y;
    for(int i=2;i<=n;i++){
		if(a[i].x>=end){
			end=a[i].y;
			ans++;
		}
	}
	cout<<ans;
	return 0;
}

/**************************************************************
	Problem: 1372
	User: linyifan
	Language: C++
	Result: Compile Error
****************************************************************/