#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
struct time {
	int begin;
	int end;
};
bool com(struct time a, struct time b) {
	return a.end < b.end;
}
int main() {
	int n;
	cin >> n;
	vector<struct time> s(n);
	for (int i = 0; i < n; i++)cin >> s[i].begin >> s[i].end;
	sort(s.begin(), s.end(), com);
	int count = 1;
	int t = s[0].end;
	for (int i = 0; i < n - 1; i++) {
		if (s[i+1].begin >= t) {
			count++;
			t = s[i + 1].end;
		}
	}
	cout << count << endl;
	return 0;
}