#include <bits/stdc++.h>
using namespace std;
int main() {
  long n, h, ma, ans = 0;
  cin >> n >> h;
  vector<long> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  ma = *max_element(a.begin(), a.end());
  sort(b.begin(), b.end());
  while (b[n - 1] > ma) {
    h -= b[n - 1];
    n--;
    ans++;
    if (h <= 0) break;
  }
  if (h > 0) {
    ans += (h / ma);
    if (h % ma != 0) ans++;
  }
  cout << ans;
}
