#include <bits/stdc++.h>
using namespace std;
struct Note{
	int bigan,end;
}a[101];
bool cmd(Note x,Note y){
	return x.end<y.end;
}
int main(){
	int n,nowend,sum=0;
	cin>>n;
	for(int i=1;i<=n;i++)cin>>a[i].bigan>>a[i].end;
	sort(a,a+n,cmd);
	sum++;
	nowend=a[1].end;
	for(int mm=2;mm<n;mm++){
		if(a[mm].bigan>=nowend)nowend=a[mm].end,sum++;
	}
	cout<<sum;
	return 0;
}

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