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