#include <bits/stdc++.h>
using namespace std;
int main() {
  int64_t n, h;
  cin >> n >> h;
  vector<int64_t> a(n), b(n);
  for (int64_t i = 0; i < n; i++) cin >> a[i] >> b[i];
  sort(begin(a), end(a));
  sort(begin(b), end(b));
  auto itr = upper_bound(begin(b), end(b), a.back());
  int64_t ans = end(b) - itr +
                (h - accumulate(itr, end(b), 0l) + a.back() - 1l) / a.back();
  cout << ans << endl;
}
