#include<bits/stdc++.h>
using namespace std;
struct node{
	int begin,end;
}m[101];
bool cmp(node x,node y)
{
	return x.end<y.end;
}
int n,nowend,ans;
int main(){
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>m[i].begin>>m[i].end;
	}
	sort(m+1,m+1+n,cmp);
	nowend=m[1].end;
	for(int i=2;i<=n;i++)
	{
		if(m[i].begin>=nowend){
			ans++;
			nowend=m[i].end;
		}
	}
	cout<<ans+1;
}
/**************************************************************
	Problem: 1372
	User: wuyunfeng
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2076 kb
****************************************************************/