#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);
  sort(b, b + N);
  long long ans = 0;
  for (int i = N - 1; i >= 0; i--) {
    if (b[i] < a[N - 1]) {
      break;
    }
    H -= b[i];
    ans++;
    if (H < 0) {
      cout << ans;
      return 0;
    }
  }
  cout << ans + (H + a[N - 1] - 1) / a[N - 1];
  return 0;
}
