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