#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  vector<int> a(N);
  vector<int> b(N);
  int A = -1;
  int ans = 0;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    A = max(A, a[i]);
  }
  sort(b.rbegin(), b.rend());
  for (int i = 0; i < N; i++) {
    if (b[i] < A) break;
    H -= b[i];
    ans++;
  }
  while (H > 0) {
    H -= A;
    ans++;
  }
  cout << ans << endl;
}
