#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  long long h;
  cin >> n >> h;
  vector<long long> a(n);
  vector<long long> b(n);
  long long a_idx = 0;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    if (a[a_idx] < a[i]) a_idx = i;
    if (a[a_idx] == a[i]) {
      if (b[a_idx] > b[i]) {
        a_idx = i;
      }
    }
  }
  long long attacks = 0;
  for (long long i = 0; i < n; i++) {
    if (i == a_idx) continue;
    if (b[i] > a[a_idx]) {
      attacks++;
      h -= b[i];
      if (h <= 0) {
        cout << attacks << endl;
        return 0;
      }
    }
  }
  if (h <= b[a_idx]) {
    attacks++;
    cout << attacks << endl;
    return 0;
  }
  long long addit = (h - b[a_idx] + a[a_idx] - 1) / a[a_idx];
  attacks += addit;
  h -= addit * a[a_idx];
  if (h <= 0) {
    cout << attacks << endl;
    return 0;
  }
  attacks++;
  cout << attacks << endl;
  return 0;
}
