#include <bits/stdc++.h>
using namespace std;
void solve() {
  int N, H;
  cin >> N >> H;
  vector<int> as(N), bs(N);
  for (int i = 0; i < N; i++) {
    cin >> as[i] >> bs[i];
  }
  sort(as.rbegin(), as.rend());
  sort(bs.rbegin(), bs.rend());
  int a = as[0], ans = 0;
  for (int b : bs) {
    if (H <= 0 || a >= b) break;
    H -= b;
    ans++;
  }
  if (H > 0) ans += ceil(H / a);
  cout << ans << endl;
}
int main(void) {
  solve();
  return 0;
}
