#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<pair<int, int> > vec(n);
  int a = 0;
  for (int i = 0; i < n; i++) {
    cin >> vec[i].first >> vec[i].second;
    a = max(a, vec[i].first);
  }
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (h <= 0) {
      break;
    }
    if (vec[i].second >= a) {
      ans++;
      h -= vec[i].second;
    }
  }
  ans += (max(h, 0) + a - 1) / a;
  cout << ans << endl;
  return 0;
}
