#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  ll N, H;
  cin >> N >> H;
  vector<ll> a(N);
  vector<ll> b(N);
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  ll a_max = *max_element(a.begin(), a.end());
  sort(b.begin(), b.end(), greater<ll>());
  ll ans = 0;
  for (ll i : b) {
    if (i > a_max) {
      H -= i;
      ans++;
      if (H < 0) break;
    } else
      break;
  }
  if (H > 0) {
    ans += (H + a_max - 1) / a_max;
  }
  cout << ans << endl;
}
