#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  long long H;
  cin >> N >> H;
  vector<long long> a(N);
  vector<long long> b(N);
  long long inpa, inpb;
  long long amax = 0;
  for (int i = 0; i < N; i++) {
    cin >> inpa >> inpb;
    a[i] = inpa;
    b[i] = inpb;
    amax = max(amax, inpa);
  }
  int ans = 0;
  for (int i = 0; i < N; i++) {
    if (amax < b[i]) {
      H -= b[i];
      ans++;
    }
    if (H <= 0) break;
  }
  if (H > 0) ans += 1 + (H - 1) / amax;
  cout << ans << endl;
  return 0;
}
