#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h, ta, tb;
  vector<long long> a, b;
  cin >> n >> h;
  for (int i = 0; i < (n); ++i) {
    cin >> ta >> tb;
    a.push_back(ta);
    b.push_back(tb);
  }
  long long cnt = 0;
  auto aiter = max_element(a.begin(), a.end());
  for (int i = 0; i < (n); ++i) {
    if (b[i] > *aiter) {
      if (h < 0) continue;
      ++cnt;
      h -= b[i];
    }
  }
  cnt += h / *aiter;
  if (h % *aiter > 0) cnt++;
  cout << cnt << endl;
  return 0;
}
