#include <bits/stdc++.h>
using namespace std;
const int SIZE = 400 + 1;
const long long int mod = 1e9 + 7;
int N, M, u, v;
int x;
int arr[SIZE];
int minDist[SIZE];
int hasrailpath[SIZE][SIZE];
int conn[SIZE][SIZE];
bool vis[SIZE];
bool contains(int N) {
  if (N < 0) N = -N;
  while (N) {
    if (N % 10 == 8) return 1;
    N /= 10;
  }
  return 0;
}
bool comp(const pair<int, int>& p1, const pair<int, int>& p2) {
  if (p1.second != p2.second) return p1.second < p2.second;
  return p1.first < p2.first;
}
int main() {
  long long int a, b, c, tb, tc;
  vector<pair<int, int> > orders;
  scanf("%d", &N);
  while (N--) {
    scanf("%d%d", &u, &v);
    orders.push_back(make_pair(u, v));
  }
  sort(orders.begin(), orders.end(), comp);
  int ans = 1;
  int prev = orders[0].second;
  for (int i = 1; i < orders.size(); i++) {
    if (orders[i].first > prev) {
      ans++;
      prev = orders[i].second;
    }
  }
  printf("%d\n", ans);
  return 0;
}
