#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> A(N);
  vector<long long> B(N);
  for (long long i = 0; i < N; i++) cin >> A.at(i) >> B.at(i);
  sort(A.begin(), A.end());
  sort(B.begin(), B.end());
  reverse(B.begin(), B.end());
  long long ans = 0;
  for (long long i = 0; i < N; i++) {
    if (B.at(i) <= A.back() || H <= 0)
      break;
    else {
      H -= B.at(i);
      ans++;
    }
  }
  ans += (H + A.back() - 1) / A.back();
  cout << ans << endl;
}
