#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];
  }
  bool t = true;
  long long a_m = 0;
  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]) break;
    H -= b[i];
    ans += 1;
    if (H <= 0) break;
  }
  if (H > 0 && H % a_m != 0) ans += 1;
  cout << ans + (long)(H / a_m) << endl;
  return 0;
}
