#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> a(N);
  vector<long long> b(N);
  for (long long i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a.begin(), a.end());
  sort(b.begin(), b.end());
  reverse(b.begin(), b.end());
  long long MAX = a[N - 1];
  long long ans = 0;
  for (long long i = 0; i < N; i++) {
    if (H < 0) {
      cout << ans << endl;
      return 0;
    }
    if (b[i] >= MAX) {
      ans++;
      H -= b[i];
    }
    if (b[i] < MAX) {
      break;
    }
  }
  cout << ans + (H + MAX - 1) / MAX << endl;
}
