#include<bits/stdc++.h>
using namespace std;
struct hd{
	int s;
	int end;
}a[110];
int n;
bool cmp(hd x,hd y){
	return x.end<y.end;
}

int main (){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i].s>>a[i].end;
	}
	sort(a+1,a+1+n,cmp);
	int c=1;
	int e=a[1].end;
	for(int i=2;i<=n;i++){
		if(a[i].s>=e){
			c++;
		    e=a[i].end;	
		}
	}
	cout<<c;
}
/**************************************************************
	Problem: 1372
	User: hongguangxi
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2076 kb
****************************************************************/