#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(NULL);
  ios::sync_with_stdio(false);
  long long N, H;
  cin >> N >> H;
  long long a[N], b[N];
  long long a_max = 0;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    a_max = a[i] > a_max ? a[i] : a_max;
  }
  sort(b, b + N, greater<long long>());
  long long count = 0;
  long long h = H;
  for (int i = 0; i < N; i++) {
    if (h <= 0) {
      break;
    }
    if (b[i] < a_max) {
      break;
    }
    h -= b[i];
    count++;
  }
  count += (h + a_max - 1) / a_max;
  cout << count << endl;
  return 0;
}
