#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  int64_t N, H;
  cin >> N >> H;
  vector<int64_t> bs;
  int64_t max_a = 0;
  for (uint32_t i = 0; i < N; i++) {
    int64_t a, b;
    cin >> a >> b;
    bs.push_back(b);
    max_a = max(max_a, a);
  }
  uint32_t count = 0;
  for (uint32_t i = 0; i < bs.size(); i++) {
    if (bs[i] > max_a) {
      H -= bs[i];
      count++;
      if (H <= 0) {
        cout << count << endl;
        return 0;
      }
    }
  }
  count += H / max_a;
  if ((H % max_a) != 0) {
    count++;
  }
  cout << count << endl;
  return 0;
}
