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