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