#include <bits/stdc++.h>
using namespace std;
int main() {
  int amo, h, jjj = 0, x;
  int wie[100001], thr[100001];
  cin >> amo >> h;
  for (int i = 0; i < amo; i++) cin >> wie[i] >> thr[i];
  sort(wie, wie + amo);
  reverse(wie, wie + amo);
  sort(thr, thr + amo);
  reverse(thr, thr + amo);
  x = wie[0];
  for (int i = 0; h > 0 && i < amo; i++) {
    h -= thr[i];
    jjj++;
  }
  if (h > 0) jjj += (h + x - 1) / x;
  cout << jjj;
  system("pause");
  return 0;
}
