#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
int main(int argc, char const* argv[]) {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int N, H;
  cin >> N >> H;
  vector<ll> A(N), B(N);
  for (int i = 0; i < N; i++) cin >> A[i] >> B[i];
  sort(A.begin(), A.end());
  sort(B.begin(), B.end());
  ll ans = 0;
  for (int i = 0; i < N; i++) {
    if (B[i] >= A[N - 1]) {
      ans++;
      H -= B[i];
    }
    if (H < 0) break;
  }
  if (H > 0) ans += (H + A[N - 1] - 1) / A[N - 1];
  cout << ans << endl;
  return 0;
}
