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