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

struct s{
	int a,b;
	bool bl = 1;
}bs[1000010];
bool cmp(s x,s y)
{
	return x.a < y.a;
}
int main()
{
	int n;
	cin >> n;
	for (int i = 1;i <= n;i++)
	{
		cin >> bs[i].a >> bs[i].b;
	}
	sort(bs + 1,bs + n + 1,cmp);
	int sum = 0;
	for (int i = 1;i <= n;i++)
	{
		if (bs[i].bl) {
			for (int j = i + 1;j <= n;j++) {
				if (bs[j].a <bs[i].b) bs[j].bl = 0;
			}
			sum++;
		}
	}
	cout << sum;
	return 0;
}