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

	
	
	
	
} 
/**************************************************************
	Problem: 1372
	User: zhuanghaoxiang
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2080 kb
****************************************************************/