#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  vector<int> b(N);
  int amax = 0;
  for (int i = 0; i < N; i++) {
    int a;
    cin >> a >> b[i];
    amax = max(a, amax);
  }
  sort(b.begin(), b.end(), greater<int>());
  int ans = 0;
  for (auto&& x : b) {
    if (H <= 0) break;
    if (x <= amax) break;
    H -= x;
    ans++;
  }
  ans += (H + amax - 1) / amax;
  cout << ans << endl;
}
