#include <bits/stdc++.h>
int N, H;
int MA;
int ans;
std::set<int> num;
std::vector<int> thr;
int main() {
  std::cin >> N >> H;
  for (int i = 1; i <= N; i++) {
    int a, b;
    std::cin >> a >> b;
    MA = std::max(a, MA);
    thr.push_back(b);
  }
  std::sort(thr.rbegin(), thr.rend());
  int all = num.size();
  for (auto u : thr) {
    if (u > MA) {
      H -= u;
      ans++;
    } else {
      break;
    }
  }
  if (H > 0) {
    ans += (H / MA);
    if (H % MA) ans++;
  }
  std::cout << ans << std::endl;
  return 0;
}
