#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h, hurimax = 0, ans = 0;
  cin >> n >> h;
  vector<long long> nage(n);
  long long huri[n];
  for (int i = 0; i < n; i++) {
    cin >> huri[i] >> nage[i];
    if (hurimax < huri[i]) hurimax = huri[i];
  }
  sort(nage.begin(), nage.end());
  for (int i = 0; i < n; i++) {
    if (nage[n - 1 - i] > hurimax) {
      h -= nage[n - 1 - i];
      ans++;
    }
  }
  if (h <= 0)
    cout << ans << endl;
  else {
    ans += (h + hurimax - 1) / hurimax;
    cout << ans << endl;
  }
}
