#include <bits/stdc++.h>
using namespace std;
const int Maxn = 1e5 + 100;
int katana_a[Maxn], katana_b[Maxn];
int N, H, maxkatana = -1, ans = 0;
int main() {
  cin >> N >> H;
  for (int i = 0; i < N; i++) {
    cin >> katana_a[i] >> katana_b[i];
    maxkatana = max(maxkatana, katana_a[i]);
  }
  for (int i = 0; i < N; i++)
    if (katana_b[i] > maxkatana) {
      H -= katana_b[i];
      ans++;
      if (H <= 0) {
        cout << ans << endl;
        return 0;
      }
    }
  ans += (H + maxkatana - 1) / maxkatana;
  cout << ans << endl;
  return 0;
}
