#include<iostream>
#include<utility>
#include<vector>
using namespace std;

bool cmp(pair<int,int>x1,pair<int,int>x2)
{return x1.second<x2.second;
}

int main(int argc,char *argv[])
{
	int count=0,size=0,sum=1;
	vector<pair<int ,int> >time;
	cin>>count;
	size=count-1;
	while(--count>=0)
	{
		int i,j;
		cin>>i>>j;
		time.push_back({i,j});//存到所对应的数组中 
	}
	sort(&time[0],&time[count],cmp);//sort是左闭右开区间 
	int cur=time[0].second;
	
	for(int i=0;i<size;i++)
	{   
	    if(time[i+1].first>=cur)
		{ 
		  sum++;
		  cur=time[i+1].second;
		}
	 } 
	 cout<<sum;
}