#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  for (int i = 0; i < (n); ++i) {
    cin >> a[i] >> b[i];
  }
  auto maxIt = max_element(begin(a), end(a));
  long long ans = 0;
  for (int i = 0; i < (n); ++i) {
    if (*maxIt < b[i]) {
      h -= b[i];
      ans++;
      if (h <= 0) {
        cout << ans << endl;
        return 0;
      }
    }
  }
  cout << ans + h / (*maxIt) + (h % (*maxIt) ? 1 : 0) << endl;
  return 0;
}
