#include <iostream>
#include <algorithm>

using namespace std;

struct Pair {
    int m, h;
} a[100500];

bool cmp(Pair p1, Pair p2) {
    return p1.h < p2.h;
}

int main() {
    int n;
    cin >> n;

    for (int i = 1; i <= n; i++)
        cin >> a[i].m >> a[i].h;

    sort(a + 1, a + n + 1, cmp);
    int ans = 0;
    int mx = -1;
    for(int i = 1; i <= n; i++){
      if (a[i].m>mx){
		  	ans++;
			  mx=a[i].h;
	  	}
    }

    cout << ans;
    return 0;

}