#include <algorithm>
#include <cstdint>
#include <functional>
#include <iostream>
#include <istream>
#include <iterator>
#include <ostream>
#include <utility>
#include <vector>

using ll = int64_t;

std::ostream& operator<<(std::ostream& os, const std::pair<ll, ll>& p){
    os << "{ " << p.first << ", " << p.second << " }";
    return os;
}

#define pa(a)do{for(auto v:(a)){std::cout<<v<<", ";}std::cout<<"\n";}while(0)

int main(){
    std::iostream::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    ll n;
    std::cin >> n;
    std::vector<ll> c(n);
    std::vector<std::pair<ll, ll>> input(n);
    for (ll i = 0; i < n; i++){
        std::cin >> input[i].first >> input[i].second;
    }
    std::sort(input.begin(), input.end());
    for (ll i = 0; i < input.size(); i++){
        c[i] = input[i].second;
    }
    std::vector<ll> f;
    f.reserve(n);
    for (ll x : c) {
        auto it = std::lower_bound(f.begin(), f.end(), x);
        if (it == f.end()) {
            f.push_back(x);
        } else {
            *it = x;
        }
        pa(f);
    }
    std::cout << f.size() << std::endl;
    return 0;
}