#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, H, MAX = -1;
  cin >> N >> H;
  vector<pair<long long, long long> > k(N);
  for (int i = int(0); i < int(N); i++) {
    long long a, b;
    cin >> a >> b;
    MAX = max(MAX, a);
    k.at(i) = make_pair(b, a);
  }
  sort(k.begin(), k.end());
  long long th, thdm = 0, cn = 0;
  for (int i = int(0); i < int(N); i++) {
    if (MAX <= k.at(i).first) {
      th = i;
      break;
    }
  }
  for (int i = int(th); i < int(N); i++) thdm += k.at(i).first;
  H = H - thdm;
  while (H > 0) {
    cn++;
    H -= MAX;
  }
  cout << cn + (N - th) << endl;
}
