#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int max = 0;
  vector<pair<int, int> > a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i].second >> a[i].first;
    if (a[i].second > max) max = a[i].second;
  }
  sort(a.begin(), a.end());
  int cnt = 0, sum = 0;
  for (int i = n - 1; i >= 0; i--) {
    if (a[i].first > max) {
      cnt++;
      sum += a[i].first;
    } else
      break;
  }
  for (; sum < h; cnt++) sum += max;
  cout << cnt << endl;
  return 0;
}
