#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
int main() {
  int n, h;
  cin >> n >> h;
  vector<pii> attack;
  for (int i = (0); i < (n); i++) {
    int a, b;
    cin >> a >> b;
    attack.emplace_back(a, 0);
    attack.emplace_back(b, 1);
  }
  sort(attack.begin(), attack.end());
  reverse(attack.begin(), attack.end());
  int cnt = 0;
  for (auto att : attack) {
    int damage = att.first;
    int a_type = att.second;
    if (a_type == 0) {
      cnt += (h + damage - 1) / damage;
      break;
    } else {
      ++cnt;
      h -= damage;
      if (h < 0) break;
    }
  }
  cout << cnt << endl;
  return 0;
}
