#include <fstream>
#include <algorithm>

using namespace std;
ifstream f("reactivi.in");
ofstream g("reactivi.out");
struct intv
{
	int st,dr;
}a[8001],v;
int n,i,nr=1;
inline bool c(const intv x,const intv y)
{
	return x.st<y.st;
}
int main()
{
    f>>n;
	for(i=1;i<=n;i++)f>>a[i].st>>a[i].dr;
	sort(a+1,a+n+1,c);
	v=a[1];
	for(i=2;i<=n;i++)
	{
		if(a[i].st<=v.dr)
		{
			v.st=a[i].st;
			v.dr=min(v.dr,a[i].dr);
		}
		else
		{
			nr++;
			v=a[i];
		}
	}
	g<<nr;
	return 0;
}