#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, count = 0, hp = 0, bb = 0, aa = 0;
  long long H, ans = 0;
  cin >> N >> H;
  vector<long long> a(N);
  vector<long long> b(N);
  for (int i = 0; i < N; i++) {
    cin >> a.at(i) >> b.at(i);
    ans = max(ans, a.at(i));
    if (ans == a.at(i)) {
      bb = b.at(i);
      aa = i;
    }
  }
  for (int i = 0; i < N; i++) {
    if (ans <= b.at(i)) {
      hp += b.at(i);
      count++;
    }
  }
  if (H - hp <= 0)
    cout << count << endl;
  else {
    H -= hp;
    while (H >= 0) {
      H -= ans;
      count++;
    }
    cout << count - 1 << endl;
  }
  return 0;
}
