#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, H;
  cin >> N >> H;
  long long ma = 0;
  vector<long long> A;
  vector<long long> B;
  for (int i = 0; i < (N); i++) {
    long long a, b;
    cin >> a >> b;
    A.push_back(a);
    B.push_back(b);
  }
  ma = *max_element(A.begin(), A.end());
  long long ans = 0;
  for (long long u : B) {
    if (u > ma) {
      H -= u;
      ans++;
      if (H <= 0) break;
    }
  }
  if (H > 0) {
    ans += H / ma;
    if (H % ma) ans++;
  }
  cout << ans << endl;
  return 0;
}
