#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, H;
  cin >> N >> H;
  long long sumab = 0;
  vector<long long> a(N);
  vector<long long> b(N);
  for (int i = 0; i < N; i++) {
    cin >> a.at(i) >> b.at(i);
  }
  sort(a.begin(), a.end());
  reverse(a.begin(), a.end());
  sort(b.begin(), b.end());
  reverse(b.begin(), b.end());
  long long A = a.at(0);
  long long countb = 0;
  long long sumB = 0;
  for (int i = 0; i < N; i++) {
    if (b.at(i) > A) {
      countb++;
      sumB += b.at(i);
    } else {
      break;
    }
  }
  cout << (H - sumB + A - 1) / A + countb << endl;
}
