#include <bits/stdc++.h>
using namespace std;
/*/
#include <atcoder/all>
using namespace atcoder;
#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector,fast-math")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC target("avx,avx2,fma")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
//*/
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,a,b) for(int i=a;i<b;i++)
#define ALL(x) (x).begin(),(x).end()
#define dbgv(x); for(auto now : x) cout << now << " "; cout << endl;
//using P = pair<int,int>;
using ll = long long;
using ull = unsigned long long;
//*/
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<int> vint;
random_device rnd;
mt19937 rng(rnd());

const int INF = 1e9+100;
void solve(){
  int n; cin >> n;
  vector<pair<int,int>> ps(n),dp(n+1,make_pair(INF,INF));
  rep(i,n) cin >> ps[i].second >> ps[i].first;
  sort(ALL(ps));
  dp[0] = ps[0];
  rep(i,n)if(i){
    auto it = lower_bound(ALL(dp),make_pair(ps[i].second,INF));
    if(*it == make_pair(INF,INF) || it->second > ps[i].first) *it = ps[i];
  }
  rep(i,n+1){
    cerr << dp[i].first << " " << dp[i].second << endl;
    if(dp[i] == make_pair(INF,INF)){
      cout << n-i << endl;
      return;
    }
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int t = 1; //cin >> t;
  rep(testcase,t) solve();
}