#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
int main() {
  int N;
  ll H;
  cin >> N >> H;
  vector<ll> a(N), b(N);
  ll amax = -1;
  for (size_t i = 0; i < (N); ++i) {
    cin >> a[i] >> b[i];
    amax = std::max(amax, a[i]);
  }
  sort(b.begin(), b.end(), std::greater<ll>());
  ll ans = 0;
  for (size_t i = 0; i < (N); ++i) {
    if (amax > b[i]) break;
    H -= b[i];
    ++ans;
    if (H <= 0) break;
  }
  ll cnt = H / amax;
  if (H % amax > 0) ++cnt;
  ans += cnt;
  cout << ans << endl;
  return 0;
}
