#include <bits/stdc++.h>
using namespace std;
struct point {
  int x;
  int y;
};
point dates[500005];
bool cmp(point a, point b) {
  if (a.y < b.y) {
    return true;
  }
  if (a.y == b.y) {
    return a.x < b.x;
  }
  return false;
}
int main() {
  cin.sync_with_stdio(false);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> dates[i].x >> dates[i].y;
  }
  sort(dates, dates + n, cmp);
  int var = dates[0].y;
  int ans = 1;
  for (int i = 1; i < n; i++) {
    if (dates[i].x > var) {
      ans++;
      var = dates[i].y;
    }
  }
  cout << ans << '\n';
  return 0;
}
