#include<bits/stdc++.h>
using namespace std;
int n,ans;
struct hd{
	int x,y;
}a[200];
bool cmp(hd c,hd d){
	 return c.y<d.y;
}

int main(){
cin>>n;
for(int i=1;i<=n;i++){
	cin>>a[i].x>>a[i].y;
	
}
sort(a+1,a+1+n,cmp);
int 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: chenyubo
	Language: C++
	Result: Wrong Answer
****************************************************************/