#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;

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));
    vi dp;
    for(auto [r,R] : rs) {
        auto it = upper_bound(all(dp),r);
        if(it==dp.end()) {
            dp.push_back(R);
        } else {
            *it=min(*it,R);
        }


    }
    cout << n-dp.size() << '\n';

}