#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, H;
  cin >> N >> H;
  long long a[N], b[N];
  long long max_a = -1;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    max_a = max(a[i], max_a);
  }
  sort(b, b + N);
  reverse(b, b + N);
  long long ans = 0;
  for (int i = 0; i < N; i++) {
    H -= b[i];
    ans++;
    if (H <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  ans += (H + max_a - 1) / max_a;
  cout << ans << endl;
  return 0;
}
