#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> A(N), B(N);
  long long max_a = 0;
  for (int i = 0; i < N; i++) {
    long long a, b;
    cin >> a >> b;
    A[i] = a;
    B[i] = b;
    max_a = max(max_a, a);
  }
  sort(B.begin(), B.end(), greater<long long>());
  long long res = 0;
  for (int i = 0; i < N; i++) {
    if (B[i] <= max_a) break;
    res++;
    H -= B[i];
    if (H <= 0) break;
  }
  if (res > 0) {
    res += (H + max_a - 1) / max_a;
  }
  cout << res << endl;
  return 0;
}
