#include 
#include 
#include 
using namespace std;

int main()
{
  vector> v;

  int n;
  cin >> n;
  for(int i = 0; i < n; i++) {
    int a, b;
    cin >> a >> b;
    v.push_back(make_pair(b, a));
  }

  sort(v.begin(), v.end());
    int res = 1;
    int vreme = v[0].first;
    for(int i = 1; i < n; i++) {
        if(vreme <= v[i].second) {
            res++;
            vreme = v[i].first;
        }
    }
    cout << res << endl;


    return 0;
}