#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  int n, hp;
  cin >> n >> hp;
  vector<ll> katana1;
  ll a_max = 0;
  for (int i = 0; i < n; i++) {
    ll a, b;
    cin >> a >> b;
    a_max = max(a, a_max);
    katana1.push_back(b);
  }
  sort(katana1.rbegin(), katana1.rend());
  ll count = 0;
  for (int i = 0; i < n; i++) {
    int cur = katana1[i];
    if (cur <= a_max) break;
    count++;
    hp -= cur;
    if (hp == 0) break;
  }
  cout << count + (hp + a_max - 1) / a_max << endl;
  return 0;
}
