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

const int maxn = 1000010;
struct Node{
	int l, r;
}a[maxn];
int n, ans = 0, f = 0;
bool cmp(Node x, Node y){
	return x.r <= y.r;
}

int main(){
	cin >> n;
	for(int i = 1; i <= n; i++){
		cin >> a[i].l >> a[i].r;
	}
	sort(a + 1, a + 1 + n, cmp);
	for(int i = 1; i <= n; i++)
		if(f <= a[i].l)
			ans++, f = a[i].r;
	cout << ans << endl;
	return 0;
}