#include <bits/stdc++.h>
using namespace std;
void solve() {
  int N, H, a, max_a = 0, ans = 0;
  cin >> N >> H;
  vector<int> b(N);
  for (int i = 0; i < N; i++) {
    cin >> a >> b.at(i);
    max_a = max(max_a, a);
  }
  sort(b.begin(), b.end());
  for (int i = N - 1; i >= 0; i--) {
    if (b.at(i) < max_a) {
      break;
    }
    H -= b.at(i);
    ans++;
  }
  ans += (H + max_a - 1) / max_a;
  cout << ans << endl;
  return;
}
int main() { solve(); }
