#include <bits/stdc++.h>
using namespace std;
int main(void) {
  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 ans;
  for (ans = 0; ans < N && H > 0 && a[0] < b[ans]; ans++) H -= b[ans];
  ans += (H + a[0] - 1) / a[0];
  cout << ans << endl;
  system("pause");
  return 0;
}
