#include <bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...) void(0)
#endif

template <class T> std::istream& operator>>(std::istream& is, std::vector<T>& v) {
    for (auto& e : v) {
        is >> e;
    }
    return is;
}

template <class T> std::ostream& operator<<(std::ostream& os, const std::vector<T>& v) {
    for (std::string_view sep = ""; const auto& e : v) {
        os << std::exchange(sep, " ") << e;
    }
    return os;
}

template <class T, class U = T> bool chmin(T& x, U&& y) {
    return y < x and (x = std::forward<U>(y), true);
}

template <class T, class U = T> bool chmax(T& x, U&& y) {
    return x < y and (x = std::forward<U>(y), true);
}

template <class T> void mkuni(std::vector<T>& v) {
    std::ranges::sort(v);
    auto result = std::ranges::unique(v);
    v.erase(result.begin(), result.end());
}

template <class T> int lwb(const std::vector<T>& v, const T& x) {
    return std::distance(v.begin(), std::ranges::lower_bound(v, x));
}

using ll = long long;

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
    int N;
    cin >> N;
    vector<pair<int, int>> v;
    for (int i = 0; i < N; i++) {
        int r, R;
        cin >> r >> R;
        v.emplace_back(r, R);
    }

    ranges::sort(v);
    multiset<int> s;
    for (auto [r, R] : v) {
        auto itr = s.upper_bound(r);
        if (itr != s.begin()) {
            itr = prev(itr);
            s.erase(itr);
        }
        s.emplace(R);
    }

    int ans = int(s.size()) - 1;
    cout << ans << "\n";
    return 0;
}