#include <bits/stdc++.h>
using namespace std;
void solve() {
  long N, H;
  cin >> N >> H;
  long max_a = 0;
  vector<long> bs(N);
  for (long i = 0; i < (N); i++) {
    long a, b;
    cin >> a >> b;
    max_a = max(max_a, a);
    bs[i] = b;
  }
  sort(bs.rbegin(), bs.rend());
  long ans = 0;
  long rest = H;
  for (auto it : bs) {
    if (it <= max_a) break;
    if (rest <= 0) break;
    rest -= it;
    ans++;
  }
  ans += rest / max_a;
  rest %= max_a;
  if (rest > 0) ans++;
  cout << ans << endl;
}
int main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout.precision(12);
  solve();
  return 0;
}
