#include <bits/stdc++.h>
using namespace std;
const long mod = 1000000007;
int main() {
  long N, H;
  cin >> N >> H;
  long res = 0;
  vector<long> A, B;
  for (int i = 0; i < N; i++) {
    long a, b;
    cin >> a >> b;
    A.push_back(a);
    B.push_back(b);
  }
  sort(A.begin(), A.end());
  reverse(B.begin(), B.end());
  long amax = A[N - 1];
  for (int i = 0; i < N; i++) {
    if (H > 0 && B[i] > amax) {
      H -= B[i];
      res++;
    }
  }
  if (H > 0) res += ((H - 1) / amax) + 1;
  cout << res << endl;
}
