#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void si(T &x) {
  register int c = getchar();
  x = 0;
  int neg = 0;
  for (; ((c<48 | c> 57) && c != '-'); c = getchar())
    ;
  if (c == '-') {
    neg = 1;
    c = getchar();
  }
  for (; c > 47 && c < 58; c = getchar()) {
    x = (x << 1) + (x << 3) + c - 48;
  }
  if (neg) x = -x;
}
long long bigmod(long long p, long long e, long long M) {
  long long ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % M;
    p = (p * p) % M;
  }
  return ret;
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long modinverse(long long a, long long M) { return bigmod(a, M - 2, M); }
void io() { freopen("/Users/MyMac/Desktop/in.txt", "r", stdin); }
const int N = 5e5 + 5;
vector<pair<int, int> > v;
bool cmp(pair<int, int> a, pair<int, int> b) { return a.second < b.second; }
int main() {
  int n;
  si(n);
  for (int i = 0; i < n; i++) {
    int a, b;
    si(a);
    si(b);
    v.push_back((make_pair(a, b)));
  }
  sort((v).begin(), (v).end(), cmp);
  int prv = v[0].second;
  int o = 1;
  for (int i = 1; i < v.size(); i++) {
    if (v[i].first > prv) {
      o++;
      prv = v[i].second;
    }
  }
  printf("%d\n", o);
  return 0;
}
