#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, cnt = 0;
  long long int h, a, maxat = 0;
  cin >> n >> h;
  vector<long long int> t(n);
  for (int i = 0; i < n; ++i) {
    cin >> a >> t[i];
    maxat = max(a, maxat);
  }
  for (long long int i : t) {
    if (i >= maxat) {
      h -= i;
      ++cnt;
      if (h <= 0) {
        cout << cnt << endl;
        return 0;
      }
    }
  }
  if (h <= 0) {
    cout << cnt << endl;
    return 0;
  }
  cout << cnt + (h / maxat + (h % maxat ? 1 : 0)) << endl;
}
