#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

struct Matryoshka {
    int r, R;
};

bool compare(const Matryoshka &a, const Matryoshka &b) { return a.R < b.R; }

int main() {
    int N;
    cin >> N;

    vector<Matryoshka> dolls(N);
    for(int i = 0; i < N; ++i) {
        cin >> dolls[i].r >> dolls[i].R;
    }

    sort(dolls.begin(), dolls.end(), compare);

    vector<int> dp(N, 1);
    for(int i = 1; i < N; ++i) {
        for(int j = 0; j < i; ++j) {
            if(dolls[j].R <= dolls[i].r) {
                dp[i] = max(dp[i], dp[j] + 1);
            }
        }
    }

    int maxDolls = *max_element(dp.begin(), dp.end());
    int operationsB = N - maxDolls;

    cout << operationsB << endl;

    return 0;
}