#include "bits/stdc++.h"
using namespace std;
#define all(x) x.begin(),x.end()
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << p.first << " " << p.second; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { string sep; for (const T &x : v) os << sep << x, sep = " "; return os; }
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#define ASSERT(...) 42
#endif
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pi;
const int oo = 1e9;
template<typename T> struct fenwick {
    int n;
    vector<T> fen;
    fenwick(){}
    fenwick(int nn) {
        fen.resize(nn+1);
        n = nn;
    }
    auto sum(int i) {
        T ans = 0;
        while(i) {
            ans=max(ans,fen[i]);
            i&=i-1;
        }
        return ans;
    }
    auto query(int r) {
        return sum(r+1);
    }
    void update(int i, T val) {
        ++i;
        while(i<=n) {
            fen[i]=max(fen[i],val);
            i+= i&(-i);
        }
    }
};
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n; cin >> n;
    vector<array<int,2>> rs(n);

    for(auto& [r,R] : rs) {
        cin >> r >> R;

    }
    sort(all(rs));
    int res=0;
    multiset<int> s;
    int cur=0;
    for(auto [r,R] : rs) {
        auto it = s.upper_bound(r);
        if(it!=s.begin()) {
            --it;
            s.erase(it);
            
        } else cur++;
        s.insert(R);



    }
    cout << cur-1 << '\n';

}