#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("reactivi.in");
ofstream fout("reactivi.out");

int n;
struct CH {
	int st, dr;
}a[50005];

bool cmp(CH& a, CH& b)
{
	if (a.dr == b.dr)return a.st < b.st;
	return a.dr < b.dr;
}

int main()
{
	int i, nr, sol;
	fin >> n;
	for (i = 1; i <= n; i++)
		fin >> a[i].st >> a[i].dr;
	sort(a + 1, a + 1 + n, cmp);
	sol = 1;
	nr = a[1].dr;
	for (i = 2; i <= n; i++)
	{
		if (a[i].st >nr)
		{
			sol++;
			nr = a[i].dr;
		}
	}
	fout << sol;
}