#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a.begin(), a.end(), greater<int>());
  sort(b.begin(), b.end(), greater<int>());
  int dmg = 0, res = 0;
  for (int i = 0; i < n && a[0] < b[i] && dmg < h; i++) {
    dmg += b[i];
    res++;
  }
  res += (h - dmg + a[0] - 1) / a[0];
  cout << res << endl;
}
