#include<bits/stdc++.h>
using namespace std;

int main(){
	int N;
	cin >> N;
	vector<pair<int, int>> p(N);
	for (int i = 0; i < N; i++) cin >> p[i].first >> p[i].second;
	sort(p.begin(), p.end(), [&](pair<int, int> l, pair<int,int> r){
		return l.second > r.second;
	});
	vector<int> X(N);
	X[0] = (1 << 30);
	int ans = 0;
	for (int i = 0; i < N; i++){
		int L = 0, R = N;
		while (R - L > 1){
			int mid = (L + R) / 2;
			if (p[i].second <= X[mid]) L = mid;
			else R = mid;
		}
		ans = max(ans, R);
		X[R] = max(X[R], p[i].first);
	}
	cout << N - ans << "\n";
}