#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
using namespace std;
using ll = long long int;
template<typename T>
ostream& operator+(ostream& out, const vector<T> &vec){
    for(const auto &x : vec){
        out<<x<<" ";
    }
    out<<"\n";
    return out;
}
template<typename T>
ostream& operator*(ostream& out, const vector<T> &vec){
    for(const auto &x : vec){
        out+x;
    }
    return out;
}
template<typename T>
istream& operator>>(istream& in, vector<T> &vec){
    for(auto &x : vec){
        in>>x;
    }
    return in;
}
void solve(){
    int n;
    cin>>n;
    vector<array<int, 2>> a(n);
    vector<int> vals;
    for(auto &[r, R] : a){
        cin>>r>>R;
        vals.push_back(r);
        vals.push_back(R);
    }
    sort(vals.begin(), vals.end());
    vals.erase(unique(vals.begin(), vals.end()), vals.end());
    for(auto &[r, R] : a){
        r = lower_bound(vals.begin(), vals.end(), r) - vals.begin() + 1;
        R = lower_bound(vals.begin(), vals.end(), R) - vals.begin() + 1;
    }
    vector<int> dp(vals.size() + 1);
    sort(a.begin(), a.end(), [](const array<int, 2> &a, const array<int, 2> &b){
        return a[1] < b[1];
    });
    for(int i=1,j=0;i<=vals.size();i++){
        dp[i] = dp[i-1];
        while(j < n && a[j][1] == i){
            dp[i] = max(dp[i], dp[a[j][0]] + 1);
            ++j;
        }
    }
    cout<<n - dp.back()<<"\n";
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
}