#include <bits/stdc++.h>
using namespace std;

struct A
{
	int a,b;
} w[1000005];

int n,now,cnt;

bool cmp(A x,A y)
{
	return x.b < y.b;
}

int main()
{
	cin >> n;
	for (int i = 1;i <= n;i++)
	{
		cin >> w[i].a >> w[i].b;
	}
	sort(w + 1,w + n + 1,cmp);
	for (int i = 1;i <= n;i++)
	{
		if (w[i].a >= now)
		{
			cnt++;
			now = w[i].b;
		}
	}
	cout << cnt;
	return 0;
}