#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
#define rep(i,a,b) for(ll i = a; i < b; i++)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
bool chmin(auto &a, auto b){if(a > b){a = b; return true;} return false;}
bool chmax(auto &a, auto b){if(a < b){a = b; return true;} return false;}

int main(){
    int n;
    cin >> n;
    vector<array<ll,2>> p(n);
    rep(i,0,n){
        cin >> p[i][0] >> p[i][1];
    }
    sort(rall(p));

    vector<int> mx(n, 1);
    rep(i,1,n){
        mx[i] = mx[i-1];

        int it = -1, ng = i;
        while(ng -it > 1){
            int md = (ng + it) / 2;
            if(p[md][0] < p[i][1]) ng = md;
            else it = md;
        }

        if(it == -1) continue;
        chmax(mx[i], mx[it] + 1);
    }

    cout << n - mx[n-1] << endl;
}