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