#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, h, cnt = 0;
  cin >> n >> h;
  vector<long int> a, b;
  for (int i = 0; i < n; i++) {
    int t, tt;
    cin >> t >> tt;
    a.push_back(t);
    b.push_back(tt);
  }
  sort(a.begin(), a.end());
  for (auto p : b) {
    if (p > a.back()) {
      cnt++;
      h -= p;
    }
  }
  if (h >= 0) {
    cnt += h / a.back();
    if (h % a.back()) cnt++;
  }
  cout << cnt << endl;
}
