#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n; cin >> n;
  vector<int> r(n), R(n); REP(i, n) cin >> r[i] >> R[i];
  {
    vector<int> ord(n);
    iota(ord.begin(), ord.end(), 0);
    ranges::sort(ord, {}, [&](const int i) -> int { return R[i]; });
    vector<int> tmp(n);
    REP(i, n) tmp[i] = r[ord[i]];
    r.swap(tmp);
    REP(i, n) tmp[i] = R[ord[i]];
    R.swap(tmp);
  }
  multiset<int> matryoshka;
  REP(i, n) {
    if (!matryoshka.empty() && *matryoshka.begin() <= r[i]) {
      matryoshka.erase(prev(matryoshka.upper_bound(r[i])));
    }
    matryoshka.emplace(R[i]);
  }
  cout << matryoshka.size() - 1 << '\n';
  return 0;
}