#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int 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.rbegin(), a.rend());
  sort(b.rbegin(), b.rend());
  int cnt = 0, max_a = a[0];
  for (int i = 0; i < n; i++) {
    if (b[i] <= max_a) break;
    h -= b[i];
    cnt++;
  }
  cnt += (h + max_a - 1) / max_a;
  cout << cnt << endl;
  return 0;
}
