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