#include <bits/stdc++.h>
using namespace std;
const long long int INF = (long long int)1e19;
int main() {
  int N, H;
  cin >> N >> H;
  vector<int> a(N), b(N);
  for (int i = (0); i < (N); ++i) cin >> a[i] >> b[i];
  sort((a).begin(), (a).end());
  sort((b).begin(), (b).end());
  int a_max = a[N - 1];
  int ans = 0;
  for (int i = N - 1; i >= 0; i--) {
    if (b[i] >= a_max) {
      H -= b[i];
      ans++;
      if (H <= 0) break;
    }
  }
  ans += (H + a_max - 1) / a_max;
  cout << ans << endl;
}
