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

#ifdef LOCAL
#include "../debug.h"
#else
#define dbg(...)
#endif
 
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int N;  cin >> N;
  vector<int> L(N), R(N);
  for(int i = 0 ; i < N ; ++i) {
    cin >> L[i] >> R[i];
  }
  vector<int> dp(N + 1), ord(N);
  iota(ord.begin(), ord.end(), 0);
  sort(ord.begin(), ord.end(), [&](int i, int j) {
    return R[i] < R[j];
  });

  for(int i = 0 ; i < N ; ++i) {
    int lo = -1, hi = i + 1;
    while(hi - lo > 1) {
      int mid = (lo + hi) / 2;
      if(L[ord[i]] >= R[ord[mid]])
        lo = mid;
      else
        hi = mid;
    }
    dp[i + 1] = max(dp[hi] + 1, dp[i]);
  }
  cout << N - dp[N] << '\n';
  
  return 0;
}