#include <bits/stdc++.h>
using namespace std;
int main(void) {
  long long n, h;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  for (int i = 0; i < (int)n; i++) cin >> a[i] >> b[i];
  sort(a.begin(), a.end());
  long long sl = a[n - 1];
  sort(b.begin(), b.end());
  auto itr = lower_bound(b.begin(), b.end(), sl);
  int k = itr - b.begin();
  long long res = n - k, d = 0;
  for (int i = k; i < n && d < h; i++) d += b[i];
  long long buf = (h - d + sl - 1) / sl;
  res += buf;
  cout << res << endl;
}
