#include<bits/stdc++.h>
using namespace std;
struct node
{	int nan,bei;
	int mn,mx;
}city[200005];
int cmp(node a,node b)
{	if(a.mx<b.mx) return 1;
	if(a.mx==b.mx)
	{	if(a.mn>=b.mn) return 1;
		else return 0;
	}
	else return 0;
}
int main()
{	int n;
	cin>>n;
	int x,y; 
	for(int i=1;i<=n;i++)
	{	cin>>x>>y;
		city[i].nan=x;
		city[i].bei=y;
		city[i].mn=min(x,y);
		city[i].mx=max(x,y);
	}
	sort(city+1,city+n+1,cmp);
	int ans=1,start=city[1].nan,end=city[1].bei;
	for(int i=2;i<=n;i++)
	{	if(city[i].nan>start&&city[i].bei>end)
		{	ans++;
			start=city[i].nan;
			end=city[i].bei;
		}
		if(city[i].mn>start&&city[i].mn>end)
		{	ans++;
			start=city[i].nan;
			end=city[i].bei;
		}
	}
	cout<<ans;
	return 0;
}