#line 1 "main.cpp"
//noya2さんお誕生日おめでとうございます！
#line 2 "/root/AtCoder/Halc-Library/Template/Template.hpp"
#include <bits/stdc++.h>
using namespace std;

#line 8 "/root/AtCoder/Halc-Library/Template/InOut.hpp"
inline void scan() {}
inline void scan(int &a) { std::cin >> a; }
inline void scan(unsigned &a) { std::cin >> a; }
inline void scan(long &a) { std::cin >> a; }
inline void scan(long long &a) { std::cin >> a; }
inline void scan(unsigned long long &a) { std::cin >> a; }
inline void scan(char &a) { std::cin >> a; }
inline void scan(float &a) { std::cin >> a; }
inline void scan(double &a) { std::cin >> a; }
inline void scan(long double &a) { std::cin >> a; }
inline void scan(std::vector<bool> &vec) {
    for (int32_t i = 0; i < vec.size(); i++) {
        int a;
        scan(a);
        vec[i] = a;
    }
}
inline void scan(std::string &a) { std::cin >> a; }
template <class T>
inline void scan(std::vector<T> &vec);
template <class T, size_t size>
inline void scan(std::array<T, size> &vec);
template <class T, class L>
inline void scan(std::pair<T, L> &p);
template <class T, size_t size>
inline void scan(T (&vec)[size]);
template <class T>
inline void scan(std::vector<T> &vec) {
    for (auto &i : vec) scan(i);
}
template <class T>
inline void scan(std::deque<T> &vec) {
    for (auto &i : vec) scan(i);
}
template <class T, size_t size>
inline void scan(std::array<T, size> &vec) {
    for (auto &i : vec) scan(i);
}
template <class T, class L>
inline void scan(std::pair<T, L> &p) {
    scan(p.first);
    scan(p.second);
}
template <class T, size_t size>
inline void scan(T (&vec)[size]) {
    for (auto &i : vec) scan(i);
}
template <class T>
inline void scan(T &a) {
    std::cin >> a;
}
inline void in() {}
template <class Head, class... Tail>
inline void in(Head &head, Tail &...tail) {
    scan(head);
    in(tail...);
}
inline void print() { std::cout << ' '; }
inline void print(const bool &a) { std::cout << a; }
inline void print(const int &a) { std::cout << a; }
inline void print(const unsigned &a) { std::cout << a; }
inline void print(const long &a) { std::cout << a; }
inline void print(const long long &a) { std::cout << a; }
inline void print(const unsigned long long &a) { std::cout << a; }
inline void print(const char &a) { std::cout << a; }
inline void print(const char a[]) { std::cout << a; }
inline void print(const float &a) { std::cout << a; }
inline void print(const double &a) { std::cout << a; }
inline void print(const long double &a) { std::cout << a; }
inline void print(const std::string &a) {
    for (auto &&i : a) print(i);
}
template <class T>
inline void print(const std::vector<T> &vec);
template <class T, size_t size>
inline void print(const std::array<T, size> &vec);
template <class T, class L>
inline void print(const std::pair<T, L> &p);
template <class T, size_t size>
inline void print(const T (&vec)[size]);
template <class T>
inline void print(const std::vector<T> &vec) {
    if (vec.empty()) return;
    print(vec[0]);
    for (auto i = vec.begin(); ++i != vec.end();) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T>
inline void print(const std::deque<T> &vec) {
    if (vec.empty()) return;
    print(vec[0]);
    for (auto i = vec.begin(); ++i != vec.end();) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T, size_t size>
inline void print(const std::array<T, size> &vec) {
    print(vec[0]);
    for (auto i = vec.begin(); ++i != vec.end();) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T, class L>
inline void print(const std::pair<T, L> &p) {
    print(p.first);
    std::cout << ' ';
    print(p.second);
}
template <class T, size_t size>
inline void print(const T (&vec)[size]) {
    print(vec[0]);
    for (auto i = vec; ++i != end(vec);) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T>
inline void print(const T &a) {
    std::cout << a;
}
inline void out() { std::cout << '\n'; }
template <class T>
inline void out(const T &t) {
    print(t);
    std::cout << '\n';
}
template <class Head, class... Tail>
inline void out(const Head &head, const Tail &...tail) {
    print(head);
    std::cout << ' ';
    out(tail...);
}
inline void Yes(bool i = true) { out(i ? "Yes" : "No"); }
inline void No(bool i = true) { out(i ? "No" : "Yes"); }
inline void Takahashi(bool i = true) { out(i ? "Takahashi" : "Aoki"); }
inline void Aoki(bool i = true) { out(i ? "Aoki" : "Takahashi"); }
inline void First(bool i = true) { out(i ? "First" : "Second"); }
inline void Second(bool i = true) { out(i ? "Second" : "First"); }
inline void Possible(bool i = true) { out(i ? "Possible" : "Impossible"); }
inline void Impossible(bool i = true) { out(i ? "Impossible" : "Possible"); }
inline void fls() { std::flush(std::cout); }
struct IOsetup {
    IOsetup() {
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
        std::cout << std::fixed << std::setprecision(16);
    }
} iosetup;
#line 8 "/root/AtCoder/Halc-Library/Template/Util.hpp"
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned int;
using pll = std::pair<ll, ll>;
using pii = std::pair<int, int>;
using vl = std::vector<ll>;
using vvl = std::vector<std::vector<ll>>;
using pdd = std::pair<ld, ld>;
using tuplis = std::array<ll, 3>;
template <class T>
using pq = std::priority_queue<T, std::vector<T>, std::greater<T>>;
constexpr ll LINF = (1LL << 62) - (1LL << 31);
constexpr int32_t INF = INT_MAX >> 1;
constexpr ll MINF = 1LL << 40;
constexpr ld DINF = std::numeric_limits<ld>::infinity();
constexpr int32_t MODD = 1000000007;
constexpr int32_t MOD = 998244353;
constexpr ld EPS = 1e-9;
constexpr ld PI = 3.1415926535897932;
const ll four[] = {0, 1, 0, -1, 0};
const ll eight[] = {0, 1, 1, 0, -1, -1, 1, -1, 0};
template <class T>
bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return true;
    } else
        return false;
}
template <class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    } else
        return false;
}
template <class T>
ll sum(const T &a) {
    return accumulate(std::begin(a), std::end(a), 0LL);
}
template <class T>
ld dsum(const T &a) {
    return accumulate(std::begin(a), std::end(a), 0.0L);
}
template <class T>
auto min(const T &a) {
    return *min_element(std::begin(a), std::end(a));
}
template <class T>
auto max(const T &a) {
    return *max_element(std::begin(a), std::end(a));
}
#line 1 "/root/AtCoder/Halc-Library/Template/Macro.hpp"
#define _overload3(_1, _2, _3, name, ...) name
#define _overload4(_1, _2, _3, _4, name, ...) name
#define _rep1(i, n) for (ll i = 0; i < (n); i++)
#define _rep2(i, a, b) for (ll i = (a); i < (b); i++)
#define _rep3(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep(...) _overload4(__VA_ARGS__, _rep3, _rep2, _rep1)(__VA_ARGS__)
#define _rrep1(i, n) for (ll i = (n) - 1; i >= 0; i--)
#define _rrep2(i, a, b) for (ll i = (b) - 1; i >= (a); i--)
#define rrep(...) _overload3(__VA_ARGS__, _rrep2, _rrep1)(__VA_ARGS__)
#define each(i, ...) for (auto&& i : __VA_ARGS__)
#define all(i) std::begin(i), std::end(i)
#define rall(i) std::rbegin(i), std::rend(i)
#define len(x) ((ll)(x).size())
#define fi first
#define se second
#define uniq(x) x.erase(unique(all(x)), std::end(x))
#define vec(type, name, ...) vector<type> name(__VA_ARGS__);
#define vv(type, name, h, ...) std::vector<std::vector<type>> name(h, std::vector<type>(__VA_ARGS__));
#define INT(...) int __VA_ARGS__; in(__VA_ARGS__)
#define LL(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ULL(...) unsigned long long __VA_ARGS__; in(__VA_ARGS__)
#define STR(...) std::string __VA_ARGS__; in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__; in(__VA_ARGS__)
#define LD(...) long double __VA_ARGS__; in(__VA_ARGS__)
#define VEC(type, name, size) std::vector<type> name(size); in(name)
#define VV(type, name, h, w) std::vector<std::vector<type>> name(h, std::vector<type>(w)); in(name)
#line 3 "main.cpp"
void solve() {
    LL(N);
    VEC(pll,mat,N);
    rep(i,N)swap(mat[i].fi,mat[i].se);
    sort(all(mat));
    multiset<ll> ser;
    for(auto &[R,r]:mat){
        auto it=ser.upper_bound(r);
        if(it!=ser.begin()){
            it--;
            ser.erase(it);
        }
        ser.insert(R);
    }
    out(len(ser)-1);
}
int main() { solve(); }
/*---------------------✂ｷﾘﾄﾘ線✂----------------------*\
| Coding by hirayuu_At.                                 |
|                                                       |
|     (　ﾟдﾟ)                                           |
| ＿(__つ/￣￣￣/＿             ∧∧                    |
|     ＼/  WA  /               /⌒ヽ)                   |
|        ￣￣￣     ／＼      i三  ∪                   |
|          . ∵ .／  .／|    〇三  |                    |
|             ∴ ＼／ ／       (/~∪                    |
|      (ﾉﾟДﾟ)ﾉ    |／           三三           終       |
|     /    /                   三三        制作・著作   |
| ￣￣￣￣￣￣                三三三       ━━━━━━━━━━   |
|                                           ⒽⒶⓁⒸ    |
\*-----------------------✂ｷﾘﾄﾘ線✂--------------------*/